Unit 4 Coordinate Geometry
                              Starters
   Lesson 1: Midpoint of a line  Lesson 8: Perpendicular
    and distance between 2             Lines
    points                          Lesson 9: Collinear points
   Lesson 2: To find the              and drawing lines
    gradient of a line              Lesson 10:Intercept –
   Lesson 3: Gradient of a line       intercept method
    making an angle with the        Lesson 11: Simultaneous
    axes                               Equations
   Lesson 4: Rearranging the  Lesson 12/13:
    equation of a straight line        Simultaneous Equations-
   Lesson 5/6: Finding the            Substitution
    equation of lines from          Lesson 14/15:
    given information                  Applications
   Lesson 7: Parallel Lines                                   1
Co-ordinate Geometry
           Lesson 1
 Midpoint of a line and distance
       between 2 points


                                   2
To find the mid point of a line
                                            Midpoint of a line
A line segment is part of a line
                                                                                         y
                                                                                    10
The mid point is exactly half way between
the end points                                                                 (x2,y2)
                                                                                     8
         ( x1 x2 ) ( y1 y2 )
  mp              ,
             2         2                                                             6
  ie we average the points
                                                                                     4
In the example
                                                                                     2
x1 , y1      ( 4, 0),                x2 , y2    0,8             (x1,y1)
                                                      –8   –6        –4   –2                 x
          ( x1       x2 ) ( y1       y2 )
mp                       ,                                                         –2
                 2               2
          ( 4 0) (0 8)
mp              ,
             2     2
mp         2, 4
                                                                                             3
Midpoint of a Line
The midpoint of the line joining two points (x1,y1) and (x2,y2) is



       .
     ( x1       x2 ) y1       y2
                    ,
            2             2                           ( x1 , y1 )




                                                                     4
Be careful when there are negatives
            x1 y1             x2 y2               It is useful to
                                                 put the correct
   x1 , y1 (6, 1),   x2 , y2   2, 3              coordinate over
                                                the top then you
         ( x1       x2 ) ( y1       y2 )            won’t get
   mp                   ,                            confused
                2               2
         (6         2) ( 1           3)
   mp                 ,
                2               2
         (6 2) ( 1 3)
   mp         ,
           2      2

         4 ( 4)
   mp     ,
         2 2
                                           mp   2, 2
                                                                    5
Sometimes you are given the midpoint
      Mid point of AB is (4,5) If A is (2,9) find B

A x1 , y1         (2,9),   B x2 , y2   ( x, y ),   mp   4,5

               (2 x) (9 y )
(4,5)               ,
                 2     2

    (2 x)                         (9 y )
  4       ,                    5
      2                             2
 8 2 x,                        10 9 y
  x       6,                     y 1

      B        (6,1)


                                                              6
Calculate the midpoint of the lines joining the following
pairs of points;

1. (9 , 4) and (6 , 2)
2. (3 , 7) and (-4 , -1)
3. (-1 , 5) and (0 , -4)
4. (-5 , 7) and (5 , -7)
5. (-2 , -4) and (3 , -6)
6. (3.7 , -1.8) and (-2.4 , 1.5)
7. (x , 2x) and (-x , -2x)
8. (p , 0) and (-p , -p)
9. (z,- 3 z) and (-z,       3 z)
                                                            7
Ex 2.1: #1a-I (1column) 2-5
      WB P170#12-25
         (15mins)



                              8
Distance between two points
    We can find the distance between two points by Pythagoras
                                                                                                     y
                                                                                                 8
    2       2        2
h       a        b                                                                   (x2,y2)
                                                                                                 7
                                                                                     x           6
    2                    2                    2
d       ( x2     x1 )           ( y2   y1 )                                                      5
                                                                                          (y2-y1)
                                                                                                4
                            2                 2
d        ( x2        x1 )       ( y2   y1 )                                                      3
                                                  (x1,y1)
                                                    x                                            2
                                                                      (x2-x1)
                                                                                                 1


                                                    –8      –7   –6   –5   –4   –3   –2    –1                1   x
                                                                                                –1


                                                            x1 y1                             x2 y2
                                              ( x1 , y1 ) ( 8,2)                ( x2 , y2 ) ( 2,6)
                                                                                                         9
Distance between two points
We can find the distance between two points by Pythagoras
        2        2       2
                                                                                                                    y
    h        a       b                                                                                          8
    d2        ( x2      x1 ) 2 ( y2     y1 ) 2                                                                  7
                                                                                                    (x2,y2)
    d         ( x2       x1 ) 2 ( y2     y1 ) 2                                                     x           6

                                                                                                                5
                                    2                    2
 d               ( x2        x1 )       ( y2      y1 )                                                   (y2-y1)
                                                                                                               4

d              (( 2) ( 8)) 2 (6 2) 2                             (x1,y1)                                        3
                                                                   x                                            2
                                                                                     (x2-x1)
d              ( 2 8) 2 (4) 2                                                                                   1

                                                                                                                                 x
d              (6) 2 (4) 2                                         –8      –7   –6   –5   –4   –3   –2    –1
                                                                                                               –1
                                                                                                                             1


d              36 16
                                                                           x1 y1                             x2 y2
d              52                                            ( x1 , y1 ) ( 8,2)                ( x2 , y2 ) ( 2,6)
d           7.2(1dp )units
                                                                                                                        10
Calculate the distance between the following points;

1. (9 , 4) and (6 , 2) = 3.6 units
2. (3 , 7) and (-4 , -1) = 10.6 units
3. (-1 , 5) and (0 , -4) = 9.1 units
4. (-5 , 7) and (5 , -7) = 17.2 units
5. (-2 , -4) and (3 , -6) = 5.4 units
6. (3.7 , -1.8) and (-2.4 , 1.5) = 6.5 units
7. (x , 2x) and (-x , -2x)      20 x units
8. (p , 0) and (-p , -p)      5 p units
9. (z,- 3 z) and (-z,      3 z) = 4z units

                                                       11
Remember




                   13       25
       5
                        7
               5
3


      4            12        24




                                  12
End of Lesson 1

Ex 2.2: #a-j odd, 2,3,4,5,7,8,9
       WB P168 #1-11



                                  13
Lesson 2

To find the gradient of a line



                                 14
To find the gradient of a line
                                                                       y
      Gradient     m                                              10       (x1,y1)

             y                                                     8
      m
             x                                                     6

           ( y2 y1 )                                               4
      m
           ( x2 x1 )                                               2



                                         –8   –6      –4     –2            x
In the example                                                    –2

             x1 y1               x2 y2             (x2,y2)

x1 , y1     ( 4,0),    x2 , y2   0,8

            (8 0)
 m
          (0 ( 4))
          8
 m
          4
 m        2
                                                                                     15
Be careful when there are negatives
               x1 y1                   x2 y2
 x1, y1        ( 9, 3),   x2 , y2      1, 4

     ( y2       y1 )           Sometimes we have unknowns
m                                     The gradient of the line between
     ( x2       x1 )
                                       (4, 2) and ( p,5) is p - 6. Find p
    (( 4) ( 3))
m                                          (5 2)
    (( 1) ( 9))                     p 6
                                           ( p 4)
    ( 4 3)
m                                   ( p 4)( p 6) 3
    ( 1 9)
                                    p 2 10 p 24 3
           1
m                                   p 2 10 p 21 0
          8
                                    ( p 7)( p 3) 0
                                     p 7, p 3
                                                                            16
End of Lesson 2

 WB P174 #26-35
  Ex 2.3: # 2-9



                  17
Lesson 3

Gradient of a line making an
    angle with the axes


                               18
To find the Gradient of a line making an angle θ
                    with the x axis
                 O                        y                                y2    y1
    tan                      Gradient =                       m
                 A                        x                                x2    x1
                                     2– 2
                                     10
                                     8
                                     6
                                     4
                                      –2 O
                                        8
                                        6
                                        4                                   y2        y1
           tan       m                    A
                                                        tan
                                                                            x2        x1

In the example                                                                                  y
                  x1 y1                   x2 y2                                            10

 x1 , y1         ( 4,0),      x2 , y2      0,8                                   (x2,y2) 8


                    (8 0)                                                                   6
 Tan
                  (0 ( 4))                                                                  4       O
                  8                                                                         2
 Tan                                                        (x1,y1)

                  4                               –8   –6             –4         –2                 x


 Tan             2                                                              A
                                                                                           –2




      Tan 1 (2)                         63.4 (1dp )                                                     19
eg find the angle 2a line with the gradient of – ¾
                2–
                10
                8
                6
                4
                2– 2
                10
                8
                6
                4

makes with the positive direction of the x axis

             3
Tan                             10
                                      y

             4
                                 8
         1       3
   tan                           6
                 4
                                 4
      36.9
                                 2
                                                  36.9           143.1
smallest angle is 36.9°
                          – 2             2   4          6   8     10    x

                                – 2




 Largest angle is    36.9 180 143.1
                                                                             20
Eg Ex 2.4

  1. Calculate the gradient of a line making the following
  angle with the positive direction of the x-axis

       a) 240
          tan 24    0.4452            gradient
       b) 1260
          tan126          1.376        gradient

   3. Calculate angle line makes with positve x axis
   given gradient is 3
            gradient          3
              tan             3             Note   gradient       undefined
                          1                          tan
                    tan           3                           1
                                                        tan              (shift tan 9999999)
                          60
                                                        90
                                                                                          21
End of Lesson 3

Ex 2.4: #1 odd, 2 all, 3 odd, 4 -7




                                     22
Lesson 4

Rearranging the equation
    of a straight line


                           23
Rearranging the equation of a straight line
If a line is written in the form      y mx c

                                   Gradient         y -intercept
Eg Ex 2.5 #1
Find the gradient of
2 y 3x 2 0                               There are two forms for straight lines

We need to make y the subject
                                                    ax by c        0
   2 y 3x 2 0                               and
   2 y 3x 2                                 y mx c
    2     3   2
      y     x     ( all of both sides by 2)
    2     2   2
        3
     y= x 1
        2
                                     3
      we can now see the gradient is and the y intercept is -1
                                     2                                     24
eg    5 y 3 x 35 0
      5y     3 x 35 ( all of both sides by 5)
       5     5    5
           -3
       y      x 7
           5
                                    -3
     we can now see the gradient is    and the yintercept is -7
                                    5
     From this we can now find the angle the line makes with the x axis
               3
        tan =-                              31     180
               5
                  1       3                149
            tan       -
                          5
                              ( tells us angle angle with Positive direction
              30.96
                              of the x axis going counter clockwise is 1490 )
              31
                                                                               25
The other form of the straight line is

 ax by               c        o
     Everything on one side =0
     x is positive
     no fractions


Rules to convert y mx c to ax by c 0
       get rid of fractions
           - whole numbers over 1
           - bottoms the same
           - multiply both sides by the bottom
       put x on the side where it is positive
       everything else on that side as well, other side =0




                                                             26
Eg
             x   3
     y
            4    5
         20          5    x   4 3
            y
         20          5   4    4 5
      20 y   5 x 12
     20    20    20
         20 y    5 x 12
         5 x 20 y        12
         5 x 20 y        12




                                    27
End of Lesson 4

 Ex 2.5: 1k-p, 2-5
    Ex 2.6: all



                     28
Lesson 5 & 6

Finding the equation of
   lines from given
      information

                          29
Revision Exercise
A (2,3),
B(-1,4) and           1. a) 3.16          b) 7.28
C(1,-3) form the         c) 6.08
vertices of a
triangle.             2. a) (0.5 , 3.5)   b) (0 , 0.5)
                         c) (1.5 , 0)
Find the
1. lengths,
                      3. a) -0.33          b) -3.5
2. midpoints and
3. gradients of all      c) 6
three lines (sides)
in the triangle.


                                                         30
Finding the equation of lines from given information
                                                  y
                                                                                     10

      ( y y1 )                                                       ( x2 , y2 )
  m                                                                                   8
      ( x x1 )
                                                                                      6
 ( x x1 )m ( y y1 )
                                                                                      4
 ( y y1 ) m( x x1 )                     2– 2
                                        10 10
                                        8 8
                                        6 6
                                        4 4
                                        2– 2
                                        6 6
                                        4 4           ( x1 , y1 )                     2

  We can find the equation given
                                                –8        –6        –4       –2                    x
  3 combinations of information                                                                2

                                                                                     –2
1)If we know the gradient (m) and one point (x1,y1)                              y
                                                                           10
  m 3,            point(2,5)                                                8

   ( y y1 )   m( x x1 )                                                     6
                                                                            4

     ( y 5) 3( x 2)                                                         2


       y 5 3x 6                                      –6        –4    –2
                                                                           –2
                                                                                     2    4            6   x


                                                                           –4
        3x y 1 0
                                                                           –6
   or y       3x 1                                                         –8
                                                                          – 10                31
2
eg Find the equation of the line with a gradient of    that
                                                    5
   passes through ( 3,4)
          2
     m      ,           point(-3,4)
         5
   ( y y1 ) m( x x1 )
               2
   ( y 4)         ( x ( 3))              5       2   14
              5                       or   y       x
              2                          5      5     5
    y 4         ( x 3)
             5                           5y    2 x 14
              2       6
    y 4         x
             5        5                  2 x 5 y 14 0
            2      14
      y       x
           5         5
                                                          32
2) If you are given two points then you can find the gradient first,
  then do as 1 above                                       x1 y1  x2y2
eg
     Find the equation of the line that passes through (4,1) and (7,3)
                                           y2 y1        3 1          2
                                      m             m           m
eg(7,3)                                    x2 x1        7 4          3
                   First find
( y y) m( x Then the either
                  x1 ) using
                       point and      or (4,1) ( y y1 )       m( x x1 )
          2           gradient
( y 3)      ( x y7) y1 m( x x1 )                              2
          3                                      ( y 1)         ( x 4)
         2      14                                            3
  y 3       x                                                2     8
         3       3                                y 1          x
       2      5                3    2    5                   3     3
   y     x                or      y   x
       3      3                                              2     5
                               3    3    3           y         x
                                3y 2x 5                      3     3
                                2x 3y 5 0

        We would get the same answer if we used either point              33
3) A (2,3), B(-1,4) and C(1,-3) form the vertices of a
triangle.

Find the equations of all three lines in the triangle.




                                                         34
4) If we are given the angle with the x axis and a point. This is similar to being
given the gradient (Extn)
Eg A line passes through (3,4) and makes an angle of 63.4 with the
positive direction of the x axis
                                           ( y y1 ) m( x x1 )
  tan 63.4 m
                                              y 4 2( x 3)
     m 2
                                               y 4 2x 6
                                                y 2x 2
                                               2x     y 2      0

     Summary: We can find the equation of a straight line given

     1) gradient (m) and one point ( x1 , y1 )
     2) two points, then you can find the gradient first, then do as 1 above
     3) the angle with the x axis and a point.


                                                                            35
End of Lesson 5 & 6

        Ex 2.7: all
     WB P178 #36-51
  Ex 2.8: 1h,I,j, 2all, 3-6
        Ex 2.9: all


                              36
Lesson 7

Parallel Lines



                 37
Parallel Lines
Parallel Lines
 Are always the same distance apart
 Never meet

If a line is written in the form      y mx c
                                      2– 2
                                      10 10
                                      8 8
                                      6 6
                                      4 4
                                      2– 2
                                      10 10
                                      8 8
                                      6 6
                                      4 4
            We can see             Gradient                    y -intercept

If lines have the same gradient then they are parallel                        y
                                                                        10


        y    2 x 6 is parallel to y   2x 1                               8

                                                                         6

                                                                         4

                                                                         2
Any line with a gradient
                                              – 10 – 8   – 6   – 4   – 2          2   4   6   8   10   x
of 2 will be parallel to these                                          – 2

                                                                       – 4

                                                                       – 6

                                                                       – 8

                                                                      – 10


                                                                                                       38
If lines two lines y         m1 x c and y   m2 x c are parallel then m1   m2
Eg Find the line through (5,7) parallel to   3 y 4x 5 0
First make y the subject so line is in the form of
 y       mx c. Then we can see the gradient

     3y 4x 5 0                                              4
                                                ( y 7)        ( x 5)
                                                           3
     3y       4x 5                                         4      20
             4   5                                y 7         x
     y         x                                          3        3
            3    3                                         4      41
                                                      y      x
            4                                             3        3
      m                                                 3        4   41
           3                                       or     y        x
then using point(5,7)                                   3       3    3
 and                                                 3y     4 x 41
 (y       y1 )   m( x x1 )
                                                    3 y 4 x 41 0          39
If a line through (3,4) and (6,a) is parallel to 4 x 2 y 5            0
Find "a"
   If lines are parallel then they must have the same gradient
                                           ( y2 y1 )
                                      m              ,
  4x 2 y 5 0                               ( x2 x1 )
   2y 4x 5                           The gradient of the two
         5                           points will be the same
    y 2x
         2                               (a 4)
    m 2                              2
                                         (6 3)
                                          a 4
                                      2
                                            3
                                      6 a 4
                                       a 10
                                                                 40
End of Lesson 7

   Ex 2.10: 2-7




                  41
Lesson 8

Perpendicular Lines



                      42
Perpendicular Lines
                   2– 2
                   10 10
                   8 8
                   6 6
                   4 4
                   2– 2
                   10 10
                   8 8
                   6 6
                   4 4

Perpendicular means: at right angles to
If lines are perpendicular then they are at right angles to each other

       We know        -ve
                                                                      y   2x 4
                                      +ve                     y
                                                        10

                                                         8

    We can see these                                     6

    lines are not                                        4

    perpendicular                                        2

                                 – 10 – 8   –6   –4   –2          2   4   6   8    10   x
                                                        –2

                                                        –4

                                                        –6

                                                        –8                y       2x 1
                                                       – 10

                                                                                   43
If two lines y m1 x c and y m2 x c are perpendicular
then
                   m1 m2    2– 2
                            10 10
                            8 8
                            6 6
                            4 4
                            2– 2
                            10 10
                            8 8
                            6 6
                            4 4        1
                            1                                     1
           ie     m1                and               m2
                           m2                                    m1               y 2x 6
                                                                      y
The gradients are negative reciprocals of each other                 yy
                                                                10

  We can see these two                                           8

  lines are perpendicular                                        6

                                                                 4
 Consider gradients of
                                                                 2

                                                                                                 x
                                     – 10   –8   –6   –4   –2             2   4    6   8   10   xx
                      1                                         –2
 m     2    and   m -
                      2                                         –4

                                                                –6
                            1
                       y      x 3                               –8
                            2
                                                            – 10                           44
Egs Ex 2.11

   Find the gradient perpendicular to 3

                                                        -1
                                            gradient is
                                                        3

                                        7
   Find the gradient perpendicular to
                                        2
                                                          -2
                                            gradient is
                                                          7

   Find the gradient perpendicular to p

                                                         -1
                                             gradient is
                                                         p

                                                               45
A (2,3), B(-1,4) and C(1,-3) form the
vertices of a triangle.

Find the equations of the
perpendicular bisectors of all three
lines


                                        46
Egs Ex 2.11

Eg Find equation of a line through (-2,3) perpendicular to 3 y    4x 7 0
     3y 4x 7                                                3     6
                                                  y 3         x
          4    7                                           4      4
      y     x               4
          3    3       m                                    3     3
                            3                        y        x
                                                           4      2
                                3
                  gradient                        4        3      3 2
                               4              or     y        x
    equation of perpendicular line is             4       4       2 2
  (y    y)   m( x x1 )                                4y     3x 6
              3                                       3x 4 y 6 0
 ( y 3)         ( x ( 2))
             4
                3
       y 3        ( x 2)
               4
                                                                        47
End of Lesson 8

Ex 2.11:#1-3,5-10 Extn 11-13
      WB p182 # 52-59



                               48
Lesson 9

Collinear points and
   Drawing lines


                       49
Collinear points and Drawing lines                              y
                                                                6
                                                                         C
Collinear Points                                                4                   (2,4)
Ie points on the same line                                      2
If points are on the same line, any two
                                          –6       –4   –2                                      x
should give the same gradient                                                2       4      6
                                                               –2
                                                   B (0,-2)
                                                               –4

                                                               –6

           y y1                                                –8
using m                                        A
           x x1                      (-3,-11)                 – 10

                                                              – 12

          ( 2 ( 11))               ( 4 ( 11))                                    ( 4 ( 2))
   mAB                       mAC                                     mBC
           (0 ( 3))                 (2 ( 3))                                       (2 (0))
                                                                                  6
           9                        15
                                                                                  2
           3                         5
                                     3                        3
           3
             gradient of AB = gradient of AC = gradient of BC
                                                                                         50
                       So these points are collinear
NOTE: if points are collinear ie on the same line we can solve for an unknown
(2,1),( 3, q),(1, 2)are colinear so all points must meet the same equation
and have the same gradient

       ( y2   y1 )        ( y y1 ) m( x x1 )
   m               ,
       ( x2   x1 )
  The gradient of any two point will be the same

        ( 2 1)                 ( 2 (q))                      2 q
   m                      m                                      3
         (1 2)                 (1 ( 3))                       4
                                 2 q                        2 q 12
         3                m
   m                            1 3                             q 14
         1
                                 2 q                        q     14
   m 3                     m
                                  4
As points are collinear these gradients must be equal
                                                                       51
Drawing lines:
To draw lines we need two pieces of information
1) 2 points- plot and join
2) 1 point and the gradient-plot point and use gradient
     to find others
3) equation – either sub in x=1,2,3 etc
               -or use gradient intercept
               - or use intercept-intercept method

For Ex 2.13 we will rearrange in the form of y=mx+c to
establish the gradient and y intercept




                                                          52
End of Lesson 9
    Ex2.12: all
  Drawing Lines:
   Ex 2.13 odd
 WB P186 #64-75
 WB P187 #76-81

                   53
Lesson 10

Intercept – intercept
      method


                        54
Intercept – intercept method
               1– 1
               4
               3
               2 2
               1– 1
               6
               5
               4
               3
               2 2

If given the line in the form ax by c    0 it is easier to plot using this method

  To find x intercept, put y = 0     Remember equation of x axis is y = 0
  To find y intercept, put x = 0              equation of y axis is x = 0
                                                    y
Eg. 2x 3y 6                                     4

  1)Cuts y axis put x     0
                                                3
         2(0) 3 y 6
                                                2
              3y 6
               y 2                              1
       This gives us (0,2)
  2)Cuts x axis put y 0            – 2   – 1            1   2   3     4     5       6   x

         2 x 3(0)     6                        –1

              2x 6                             –2
                x 3
        This gives us (3,0)                                                     55
y
                                                   4

If given the graph
                                                   3
We can read the equation of the graph
                                                   2
1) gradient intercept method
                                                   1

               2
         y       x 2
              3                         –2   –1             1   2    3   4   5   6    x


                                                  –1
2) Find gradient
                                                  –2
       y2    y1
  m                    Use gradient and point (3,0)
       x2    x1
                                                              3           2     3
       (0 2)            ( y y) m( x x1 )                   or    y          x 2
  m                                                           3          3      3
       (3 0)                         2
                         ( y 0)        ( x 3)                   3y       2x 6
         2                          3
   m                             2                              2x 3y 6 0
        3                   y      x 2
                                3
                                                                                 56
End of Lesson 10

    Ex 2.14all
    Ex 2.15 all



                   57
Lesson 11

Simultaneous Equations



                         58
Simultaneous Equations
Simultaneous equations represent 2 lines on a graph that may intersect

We have three methods of finding the point of intersection

1) Graphing- either plot or use calculator
2) Elimination
3) Substitution (covered tomorrow)




                                                                    59
2)Elimination
Line up equations x over x
                  y over y
Sometimes we may need to rearrange to do this
Decide what to eliminate.
      i.e. what number is, or can we get, the same
Do we need to add or subtract to eliminate?
 7x y 1   1              7x y 1                 4x 3y     3
 4x 3y  3 2              7(0) y 1               4(0) 3( 1)   3
3 (7 x y 1)             Multiply y 1
                                 equation 1          Correct
                        by 3 to make the y
 4 x 3 y First write out Now ytheysame are the Sub y=-1
             3             termthe 1  terms
         equations across same but have opposite back into the
 21x 3 y 3
            the page         signs so we can add     second
  4x 3y       3         Sub x=0 back               equation to
    25 x 0              into equation Lines intersect at (0, 1)
                                                      check
                                1
    x   0                                                         60
Examples


        3
y         x 5         and     y   2x 6
       4



    4 y 3x       25
    2 y 5x   7

    On Graphics Calculator either;
    • Graph equations then - G-solve, intersect,   Answer (4,2)
    • Solve Simultaneous Equations in Equation Mode




*                                                                 61
4x 7 y     20
    10 x 5 y   25




*
                    62
Ex 2.18 #2


 4x 2 3y
         8
   5   2
 x 1 y 2
          4
  2   3




              63
End of Lesson 11

  Ex 2.17:1-17 odd
 Ex 2.18 1-5 Extn all



                        64
Lesson 12 & 13

Simultaneous Equations
    - Substitution


                         65
Simultaneous Equations
3) Substitution
If we know what x or y is, then in the second equation, we can put what
x or y is instead of writing x or y.
Hence we have the whole equation with only one variable.
  Eg.    y 5 4 x, 1            y 5 4 x,              10 x 7 y    1
        10 x 7 y  1 2          y 5 4(2)              10(2) 7( 3)          1
    10 x 7(5 4 x)        1      y 3                   20 21 1
                                   Sub
                     First write out                     Correct
    10 x   35 28x equations acrossinto 2
                     1           1
                                     the               Now we can sub
                                                        y=-3 into the
            18x  36 It is sensible to
                 page.
                                                       second equation
                 write the y= equation
              x 2          first                           to check
                                Now we sub
                                  x=2 back       Point of intersection (2,-3)
                                into the first
                                  equation
                                                                              66
Example
    y   x 4
    3x 2 y 2 0




*                67
Example
     y 3x 9
     4 x y 13




*
                68
Example
    y    2x 3
    y   x 9




*
                  69
Example

    y   3x 1
    y   3x 5




               Lines have the same gradient
               They are parallel.
               No solution possible


*
                                              70
End of Lesson 12 & 13

Ex 2.19 #1-15 odd Extn 16-18
   Applications: Extra sheet
     Ex 5.5 1-14 Extn all


                               71
Lesson 14 & 15

    Applications of
Simultaneous Equations


                         72
End of Lesson 14 & 15
        Applications:
   Ex 2.20: 1-15 Extn all
       Ex 16.17 sheet
           RUR Q
Merit & Excellence Questions
       WB P 192 #1-7
           RUR Q
Exam Excellence Q 2.4 W/S
                               73
Starters
   Lesson   1          Lesson   9
   Lesson   2          Lesson   10
   Lesson   3          Lesson   11
   Lesson   4          Lesson   12
   Lesson   5          Lesson   13
   Lesson   6          Lesson   14
   Lesson   7          Lesson   15
   Lesson   8
                                       74
Starter Lesson 1
  Find the equation and list features
                                   y
                                 10
                                  9
                                  8
                                  7
                                  6
                                  5
                                  4
                                  3
                                  2
                                  1

– 5   – 4    – 3   – 2    – 1           1   2   3   4   5   x
                                 – 1
                                 – 2
                                 – 3
                                 – 4
                                 – 5
                                 – 6
                                 – 7
                                 – 8
                                 – 9
                                – 10


                                                            75
Answers Starter Lesson 1          y
                             10
                              9
                              8
                              7
                              6
                              5
                              4
                              3
                              2
                              1

– 5   – 4   – 3   – 2   – 1 – 1       1   2       3     4      5   x
                            – 2
                            – 3
                            – 4
                            – 5
                            – 6
                            – 7
                            – 8
                            – 9
                           – 10


y k ( x 1)( x 3)( x 5)
                                                      (0,-5)
Sub in (0, 5)
 5 k ( 1)(3)(5)
                                                  1
 5    15k                                     y     ( x 1)( x 3)( x 5)
                                                  3
      1
k
      3                                                                  76
y

Starter Lesson 2                                    10
                                                     9
                                                     8
                                                     7
                                                     6
                                                     5
1) Find the equation                                 4
                                                     3
and list features                                    2
                                                     1

                       – 5   – 4   – 3   – 2   – 1 – 1       1   2   3   4    5   x
                                                   – 2
                                                   – 3
                                                   – 4
                                                   – 5
                                                   – 6
                                                   – 7
                                                   – 8
                                                   – 9
                                                  – 10




2) Find the midpoint of A(-2,-5) B(3,1)
and the distance between the two points

3) Sketch the graph of y                 2 x 1, x 3
                                                                             77
1)
                              10
                               9
                                   y
                                                                        Answers
                                                                        Lesson 2
                               8
                               7
                               6
                               5
                               4
                               3
                               2
                               1

 – 5   – 4   – 3   – 2   – 1 – 1       1   2       3     4      5   x
                             – 2
                             – 3
                             – 4
                             – 5
                             – 6
                             – 7
                             – 8
                             – 9
                            – 10


y k ( x 2)( x 1)( x 5)
                                                       (0,-4)
Sub in (0, 4)
 4 k ( 2)(1)(5)
                                                   2
 4    10k                                      y     ( x 2)( x 1)( x 5)
                                                   5
       2
k
       5                                                                           78
Answers Lesson 2
2)

A ( 2, 5),       B (3,1)
      x1       x2 y1       y2   d    ( x2   x1 ) 2 ( y2   y1 ) 2
mp               ,
           2           2             ((3) ( 2)) 2 ((1) ( 5)) 2
       2 3 5 1
          ,                          (3 2) 2 (1 5) 2
        2   2
      1 4                            (5) 2 (6) 2
       ,
      2 2                            25 36
      1                               61
        , 2
      2                             7.8(1dp)

                                                                   79
Answers Lesson 2
                            y
                       8
                       7
                       6
                       5
                       4
                       3
                       2
                       1

    – 3   – 2   – 1             1   2    3     4     5      6   x
                      – 1
                      – 2
                      – 3
                      – 4
                      – 5




y   2 x 1, x 3                      We have a hole at x=3



                                                                    80
Starter Lesson 3
 1) Accurately sketch the graph              2x 1
                                        y
                                             x 5
 That means properly
 1) Cuts x axis y 0
 2) Cuts y axis x   0
 3)Vertical asymptote y
 4) Horizontal asymptote x

 2) What transformation maps y    x2   9 onto y   9   x2

 3) Sketch the graph of y 3x 5, x                 2



                                                           81
Q1)
                                                                                       y
1) Cuts x axis y   0                                                             15                            2x 1
                                                                                 14
                                                                                 13                y
2x 1 0                                                                           12
                                                                                 11                            x 5
                                                                                 10
                                                                                  9
2x 1                                                                              8
                                                                                  7
                                                                                  6
                                                                                  5
    1                                                                             4
x                                                                                 3
                                                                                  2
    2                                                                             1
                                                                                                                            x
                       – 15– 14– 13– 12– 11– 10 – 9 – 8 – 7 – 6 – 5 – 4 – 3 – 2 ––11           1   2       3   4       5
                                                                                 – 2
2) Cuts y axis x 0                                                               – 3
                                                                                 – 4
                                                                                 – 5
        2(0) 1                                                                   – 6
                                                                                 – 7
y                                                                                – 8
                                                                                 – 9
        (0) 5                                                                   – 10


         1
y                                                  4) Horizontal asymptote x
        5
                                                          2       1                                2x
                                                                                                    x
                                                                                                                   1
                                                                                                                   x
    3)Vertical asymptote y                         y                                       y           x       5
                                                                  5                                    x       x
    x 5 0                                                 2                                  2
    x     5                                        y                                       y
                                                                                             1
                                                   y      2                                y 2
                                                                                                                           82
2)                                               y
                                           10
                                            9
                                            8
                                            7
                                            6
                                            5
                                            4
                                                                     y           x2 9
                                            3
                                            2
                                            1
     – 10 – 9 – 8 – 7 – 6 – 5 – 4 – 3 – 2 ––11       1   2   3   4   5       6    7   8   9   10        x
                                           – 2
                                           – 3
                                           – 4
                                           – 5
                                           – 6
                                           – 7                           y       9 x2
                                           – 8
                                           – 9
                                          – 10




Reflection in the x axis


                                                                                                   83
y
                                      10
                                       9
                                       8
                                       7
                                       6
                                       5
                                       4
                                       3
                                       2
                                       1
   – 5   – 4   – 3       – 2   – 1    – 1        1      2      3       4   5        x
                                      – 2
                                      – 3
                                      – 4
                                      – 5
                                      – 6
                                      – 7
                                      – 8
                                      – 9
                                     – 10
                                     – 11
                                     – 12
                                     – 13
                                     – 14
                                     – 15



y 3x 5, x            2                      We have a hole at x = -2



                                                                               84
Starter Lesson 4
1) Accurately sketch the graph
                                           x 3
  That means properly                 y
                                           x 4
  1) Cuts x axis y 0
  2) Cuts y axis x   0
  3)Vertical asymptote y
  4) Horizontal asymptote x


2) What transformation maps y ( x 2)2 onto y   ( x 2)2
                                  3
3) Sketch the graph of y            x 4, x 1
                                  4
                                                         85
Q1)
                                                                                       y
                                                                                 15                            x 3
                                                                                 14
                                                                                 13                y
1) Cuts x axis y   0                                                             12
                                                                                 11                            x 4
                                                                                 10
                                                                                  9
x 3 0                                                                             8
                                                                                  7
                                                                                  6
x 3                                                                               5
                                                                                  4
                                                                                  3
                                                                                  2
2) Cuts y axis x 0                                                                1
                                                                                                                        x
                       – 15– 14– 13– 12– 11– 10 – 9 – 8 – 7 – 6 – 5 – 4 – 3 – 2 ––11       1   2       3       4   5
                                                                                 – 2
        (0) 3                                                                    – 3
                                                                                 – 4
y                                                                                – 5
        (0) 4                                                                    – 6
                                                                                 – 7
                                                                                 – 8
                                                                                 – 9
          3                                                                     – 10
y
         4                                         4) Horizontal asymptote x
                                                                                               x           3
                                                                 3                             x           x
    3)Vertical asymptote y                         y                                   y       x           4
                                                                 4                             x           x
    x 4 0                                                                                   1
    x     4                                        y                               y
                                                                                            1
                                                   y 1                                     y 1
                                                                                                                       86
2)                                y
                            10
                             9
                             8
                             7                                y       ( x 2) 2
                             6
                             5
                             4
                             3
                             2
                             1
     –5   –4   –3   –2   – 1– 1       1   2   3   4   5   6       7      8   x
                            –2
                            –3
                            –4
                            –5
                            –6
                            –7                            y       ( x 2) 2
                            –8
                            –9
                           – 10

Reflection in the x axis
                                                                                 87
y
                                    3
                                    2
                                    1

    – 5   – 4   – 3   – 2   – 1                1    2     3     4      5   x
                                   – 1
                                   – 2
                                   – 3
                                   – 4
                                   – 5
                                   – 6
                                   – 7
                                   – 8
                                   – 9
                                  – 10




     3                                       We have a hole at x = 1
y      x 4, x 1
    4
                                                                               88
Starter Lesson 5
1) Accurately sketch the graph
                                     2x 1
 That means properly             y
 1) Cuts x axis y 0                  x 4
 2) Cuts y axis x 0
 3)Vertical asymptote y
 4) Horizontal asymptote x
 List Features




2) Sketch the graph of y ( x 1)(3 x)( x 2)


                                             89
Q1)
                                                                                         y
1) Cuts x axis y   0                                                               15                    2x 1
                                                                                   14
                                                                                   13
                                                                                                 y
2x 1 0                                                                             12
                                                                                   11
                                                                                                         x 4
                                                                                   10
                                                                                    9
2x 1                                                                                8
                                                                                    7
                                                                                    6
                                                                                    5
    1                                                                               4
x                                                                                   3
                                                                                    2
    2                                                                               1
                         – 15– 14– 13– 12– 11– 10 – 9 – 8 – 7 – 6 – 5 – 4 – 3 – 2 ––11       1       2   3    4   5    x
2) Cuts y axis x 0                                                                 – 2
                                                                                   – 3
                                                                                   – 4
                                                                                   – 5
      2(0) 1                                                                       – 6
                                                                                   – 7
y                                                                                  – 8
      (0) 4                                                                        – 9
                                                                                  – 10


       1
y                                                4) Horizontal asymptote x
      4                                                                                          2x       1
                                                         2       1                                x       x
                                                  y                                 y             x      4
3)Vertical asymptote y                                           4                                x      x

x 4 0                                                    2                             2
                                                  y                                 y
x      4                                                                               1
                                                  y     2                            y 2
                                                                                                                  90
Features
                1
x intercept x
                2
                1
y intercept y
               4
Vertical asymptote x   4
Horizontal asymptote y 2
fundemental discontinuity at x -4
point symmetry at (-4,2)
axis of symmetry y x 6, y        x 2
x      ,y 2
x        ,y 2

                                       91
y
                                       8
                                       7
                                       6
                                       5
                                       4
                                       3
                                       2
                                       1

       – 5   – 4   – 3   – 2   – 1              1   2   3   4   5   x
                                      – 1
                                      – 2
                                      – 3
                                      – 4
                                      – 5
                                      – 6
                                      – 7
                                      – 8
                                      – 9
                                     – 10




y   ( x 1)(3 x)( x 2)

                                                                        92
Starter Lesson 6
1) Accurately sketch the graph
                                          3x 4
 That means properly                  y
 1) Cuts x axis y 0                        x 2
 2) Cuts y axis x 0
 3)Vertical asymptote y
 4) Horizontal asymptote x
 List Features



 2) Sketch the graph of          x 2 ( y 1) 2   25
 List Features

                                                     93
Q1)
                                                                     y
                                                               15                                      3x 4
1) Cuts x axis y 0                                             14
                                                               13
                                                                                               y
                                                               12
                                                               11
                                                                                                        x 2
3x 4 0                                                         10
                                                                9
                                                                8
3x 4                                                            7
                                                                6
                                                                5
                                                                4
    4                                                           3
                                                                2
x                                                               1
    3                    – 10 – 9 – 8 – 7 – 6 – 5 – 4 – 3 – 2 ––11
                                                               –2
                                                                         1   2   3    4   5    6   7   8   9 10   x

                                                               –3
2) Cuts y axis x 0                                             –4
                                                               –5
                                                               –6
    3(0) 4                                                     –7
                                                               –8
y                                                              –9
                                                              – 10
     (0) 2
y     2                   4) Horizontal asymptote x
                                                                                     3x       4
                                   3          4                                       x        x
                           y                                             y            x       2
3)Vertical asymptote y                        2                                       x       x

x 2 0                              3                                        3
                           y                                             y
x     2                                                                     1
                           y       3                                      y 3
                                                                                                              94
Features
                     4
x intercept x
                     3
y intercept y   2
Vertical asymptote x     2
Horizontal asymptote y 3
fundemental discontinuity at x -2
point symmetry at (-2,3)
axis of symmetry y x 5, y       x 1
x     ,y     3
x       ,y       3

                                      95
y
                                                              6

  x2        ( y 1) 2     25                                   5

                                                              4

                                                              3
Centre(0,1)                                                   2

Radius =5units                                                1


Y intercepts (0,6)and(0,-           –5   –4   –3   –2   –1            1   2   3   4   5   x
                                                             –1
4)
                                                             –2

Max(0,6), Min(0,-4)                                          –3

                                                             –4

                                                             –5
                                0
x2     y2    25 translated by
                                1




                                                                                          96
Q1)
                       Starter Lesson 7
  Find the equation, and list features
                               y
                          15
                          14
                          13
                          12
                          11
                          10
                           9
                           8
                           7
                           6
                           5
                           4
                           3
                           2
                           1

       –5 –4 –3 –2 –1              1   2   3   4   5   6   7   8   9   10   x
                    –     1
                    –     2
                    –     3
                    –     4
                    –     5

                                                                            97
Features
x intercept x    4.6
                2
y intercept y 7
                3
Vertical asymptote x 3
Horizontal asymptote y 5
fundemental discontinuity at x 3
point symmetry at (3,5)
axis of symmetry y x 2, y          x 8
x     ,y     3
x       ,y       3

                                         98
2)What transformation will map
x2   y2    1 on to the graph x 2    y 2 16
                                         y
                                     5

                                     4

                                     3

                                     2

                                     1


          –5   –4   –3   –2    –1            1   2   3   4   5   x
                                    –1

                                    –2

                                    –3

                                    –4

                                    –5

                                                                     99
Image radius
SF
     Object radius
     4
SF
     1
SF 4
Enlargement about (0,0) of scale factor 4


                              Must have
                               centre
                                            100
3) What transformation maps y              x 2 on to y      ( x 3)2 5
                                                y
                                            8
                                            7
Translation by                              6
                                            5
             3
the vector                                  4
             -5                             3
                                            2
                                            1

                  –5   –4   –3   –2   –1            1   2   3   4   5   6   7     x
                                           –1
                                           –2
                                           –3
                                           –4
                                           –5
                                           –6
                                                                                101
Starter Lesson 8
1) Prove that A(-4,-4), B(1,6), C(11,1) form a
right angled isosceles triangle




                                                 102
1– 1
10 10
9 9
8 8
7 7
6 6
5 5
4 4
3 3
2 2
1– 1
12
11
10
9
8 8
7 7
6 6
5 5
4 4
3 3
2 2
        1) Prove that A(-4,-4), B(1,6), C(11,1) form a
        right angled isosceles triangle
                                     y
                                10
                                 9
                                 8
                                 7           (1,6)
                                 6
                                 5               B
                                 4
                                 3                                            C (11,1)
                                 2
                                 1

         –8 –7 –6 –5 –4 –3 –2 ––1
                               1         1   2   3   4   5   6   7   8   9   10 11 12   x

                               –2
                               –3
                               –4
              A                –5
                               –6
              (-4.-4)          –7
                               –8
                               –9
                              – 10




                                                                                            103
y y1
A( 4, 4), B(1,6), C (11,1)                           m
                                                     y           x x1
                                                10
      6 ( 4)                                     9
                                                             (1,6)
mAB                                              8
                                                 7
      1 ( 4)                                     6               B
                                                 5
      10                                         4
                                                 3
                                                 2
       5                                         1
                                                                                                        (11,1)

      2                  –8 –7 –6 –5 –4 –3 –2 ––1
                                               1         1   2   3   4   5   6   7   8   9   10 11 12    x   C
                                               –2
                                               –3
                                               –4
                               A               –5
                                               –6
      1 6                          (-4.-4)     –7
mBC                                            –8
      11 1                                     –9
                                              – 10
        5
      10                      1
                         2         1 as gradients multiply to give -1
        1                    2
       2                 they are at right angles
                                                                                                                 104
d AB   ( x x1 ) 2 ( y   y1 ) 2         d AC    ( x x1 ) 2 ( y   y1 ) 2

d AB   ( 4 1) 2 ( 4 6) 2               d AC    ( 4 11) 2 ( 4 1) 2

d AB   ( 5) 2 ( 10) 2                  d AC    ( 15) 2 ( 5) 2
d AB   25 100                          d AC    225 25
d AB   125                             d AC    250


                                 Because 2 sides are equal and one
d BC   ( x x1 ) 2 ( y   y1 ) 2
                                 is not equal, therefore the triangle is
d BC   (1 11) 2 (6 1) 2          isosceles

d BC   ( 10) 2 (5) 2             We proved before that AB is
                                 Perpendicular to BC so this is a right
d BC   100 25                    angled isosceles triangle
d BC   125



                                                                           105
Starter Lesson 9

 1)Find the equation of the line through
 (9,1) and (4,7)




 2)Find the equation of the line through
 (3,2) and (3,10)




                                           106
1)Find the equation of the line through
(9,1) and (4,7)
     y2 y1                           Equation
m                                y    y1   m( x x1 )
     x2 x1
    7 1                                      6
m                                y    1        ( x 9)
    4 9                                      5
     6                                       6     54
m                                y    1        x
      5                                      5      5
                                         6      59
                                 y         x
                                         5       5
                                 5y     6 x 59 0

                                                        107
2)Find the equation of the line through
(3,2) and (3,10)
     y2 y1
m
     x2 x1
     10 2
m
      3 3
m undefined
We know lines with an undefined gradient
arevertical and so x
In this case x 3

                                           108
Starter Lesson 10

1) Find the line through the point (5,4) parallel
to the line 3x y 2 0
                     3
2)Draw the lines y     x 5
                     4
                      4
                   y    x 2
                      3

3)Prove the above lines are perpendicular
                                                    109
1) Find the line through the point (5,4) parallel
to the line 3x y 2 0

  y   3x 2     gdt     3   pt (5, 4)
  y   y1   m( x x1 )
  y 4 3( x 5)
  y 4 3x 15
  y   3x 11




                                                    110
3
2)Draw the lines y           x5
                           4
                          4
                     y       x 2
                          3
3)Prove the above lines are perpendicula                    r
                                y
                            5
                                                                 3 4
                            4                                             1
                            3
                                                                 4 3
                            2
                                                                As gradients multiply to = -1
                            1
                                                                  Lines are perpendicular

  –5   –4   –3   –2   –1            1   2   3   4   5   x
                           –1

                           –2

                           –3

                           –4

                           –5

                                                                                          111
Starter Lesson 11
1) Find the equation of the line that passes
through (1,8) and (6,8)

2) Use the intercept- intercept method to plot
6x 4 y 3

 3) Find the line through the point (1,4)
 perpendicular to the line 4 x   y 3 0

                                               112
1) Find the equation of the line that passes
through (1,8) and (6,8)
     y2   y1
m
     x2   x1
  8 8
m                     Line has a gradient of zero so horizontal
  6 1
  0                       y   ?
m
  5                   both y coordinates are 8
m 0                     y 8




                                                            113
2) Use the intercept- intercept method to plot
6x 4 y 3                                    y

Cuts x axis y     0                             5

6 x 4(0) 3                                      4

                                                3
6x 3
                                                2
    3
x
    6                                           1

    1                                                                     x
x                     –5   –4   –3   –2   –1        1   2   3   4    5
    2                                          –1

Cuts y axis x 0                                –2

6(0) 4 y 3                                     –3
    4y    3                                    –4
          3                                    –5
y
         4


                                                                    114
3) Find the line through the point (1,4) perpendicular
to the line 4 x   y 3 0                1
                              m                (1, 4)
4x 3 y                                 4
y 4x 3                        y   y1       m( x x1 )
m 4                                      1
                              y   4        ( x 1)
        1                                4
m                                        1     1
       4                      y   4        x
                                         4     4
                                     1     1 16
                              y        x
                                     4     4 4
                                     1     17
                              y        x
                                     4      4
                              x   4 y 17 0
                                                         115
Lesson 12 Starter
1) Solve
2y x 2
5 x 2 y 10 0

                3x 1
2) Sketch y
                x 2
and list features
That means properly
1) Cuts x axis y 0
2) Cuts y axis x   0
3)Vertical asymptote y
4) Horizontal asymptote x

                               116
1) Solve
2y x       2       5 x 2 y 10 0                  2y x      2
5 x 2 y 10 0       5(3) 2 y 10 0                2(2.5) 3 2
                   15 2 y 10 0                  5 3 2
 x 2y          2   5 2y
                                                    true
5 x 2 y 10         y   2.5
4 x 12
                                   (3, 2.5)
x 3                                Checked on the
                                   calculator of course




                                                           117
3x 1                                                                      y
                                                                                                      3x 1
2) Sketch y         and list features                                              15
                                                                                   14            y
               x 2                                                                 13
                                                                                   12                 x 2
                                                                                   11
1) Cuts x axis y   0                                                               10
                                                                                    9
                                                                                    8
                                                                                    7
3x 1 0                                                                              6
                                                                                    5
                                                                                    4
3x 1                                                                                3
                                                                                    2
                                                                                    1

    1                    – 15– 14– 13– 12– 11– 10 – 9 – 8 – 7 – 6 – 5 – 4 – 3 – 2 ––11
                                                                                   – 2
                                                                                             1    2   3    4   5     x
x                                                                                  – 3
                                                                                   – 4
    3                                                                              – 5
                                                                                   – 6
                                                                                   – 7
2) Cuts y axis x 0                                                                 – 8
                                                                                   – 9
                                                                                  – 10
   3(0) 1
y
    (0) 2                                         4) Horizontal asymptote x
                                                                                                 3x   1
     1                                                   3       1                                x    x
y                                                 y                                 y             x   2
    2                                                            2                                x   x

3)Vertical asymptote y                                   3                             3
                                                  y                                 y
x 2 0                                                                                  1
x    2                                            y      3                           y 3
                                                                                                               118
Features
                1
x intercept x
                3
                1
y intercept y
                2
Vertical asymptote x    2
Horizontal asymptote y 3
fundamental discontinuity at x   2
point symmetry at (-2,3)
axis of symmetry y x 5, y        x 1
x      ,y 3
x        ,y 3

                                       119
Starter Lesson 13
1) Find the line perpendicular to 5 y 4 x 7   0 which
passes through the point (3,1)



2) If (3,4) (6,2) (8,a) are collinear
Find a




                                                        120
1) Find the line perpendicular to 5 y 4 x 7 0 which
passes through the point (3,1)
5y -4 x 7
    4     7
y      x
   5      5
     4      5
m      ,m
    5       4
y y1 m( x x1 )
       5
y 1      ( x 3)
       4
    5     11
y     x
    4      4
5 x 4 y 11 0
                                                      121
2) If (3,4) (6,2) (8,a) are collinear
Find a
      y2 y1
m                                     if lines are collinear they have the same gdt
      x2 x1
    2 4                                 2 a 2
m
    6 3                                3 8 6
      2                                 2 2 a 2 3
m
     3                                  2 3     2 2
                                         4 3(a 2)
                                         4 3a 6
                                      2 3a
                                          2
                                      a
                                          3


                                                                           122
Starter Lesson 14
1)Show that the line through (0,4) and (4,1) is
perpendicular to the line through (3,6) and (-3,-2)


2)Find the midpoint of A(4,2) and B(10,10)




                                                      123
1)Show that the line through A(0,4) and B(4,1) is
perpendicular to the line through C(3,6) and D(-3,-2)
       y2    y1                               y2    y1
mAB                                   mCD
       x2    x1                               x2    x1
       1 4                                        2 6
mAB                                  mCD
       4 0                                        3 3
         3                                        8
mAB                                  mCD
        4                                         6
                                              4
                                     mCD
                                              3
as mAB mCD           1
       3 4
                  1 lines are perpendicular
      4 3


                                                         124
2)Find the midpoint of A(4,2) and B(10,10)
       ( x1       x2 ) ( y1       y2 )
  m                   ,
              2               2
        (4 10) (2 10)
  m           ,
           2      2
        14 12
   m      ,
         2 2
   m    7, 6



                                             125
Starter Lesson 15
Prove that the points A(-3,7) B(9,15) C(5,-5)
form a right angled isosceles triangle




                                            126
Prove that the points A(-3,7) B(9,15) C(5,-5)                            d AB    ( x2    x1 ) 2 ( y2   y1 ) 2
form a right angled isosceles triangle                                   d      (9 ( 3)) 2 (15 7) 2
                           y                                             d      122 82
                     18
                     17                                                  d      208
                     16
                     15                           B                      d AC    ( x2    x1 ) 2 ( y2   y1 ) 2
                     14
                     13
                     12                                                  d      (5 ( 3)) 2 ( 5 7) 2
                     11
                     10                                                  d      82 122
                      9
                      8
  A                   7                                                  d      208
                      6
                      5                                                  d BC    ( x2    x1 ) 2 ( y2   y1 ) 2
                      4
                      3
                      2                                                  d      (9 5) 2 (15 ( 5) 2
                      1
  – 5 – 4 – 3 – 2 – –1 1       1 2 3 4 5 6 7 8 9 10 x                    d      42 202
                    –2
                    –3                                                   d      416
                    –4
                    –5
                    –6                     C            As two sides are the same and one is different,
                    –7
                    –8                                  this proves that the triangle is isosceles


                                                                                                                127
y2   y1                 y2   y1
mAB                      mAC
        x2   x1                 x2   x1
         15 7                      5 7
       9 ( 3)                   5 ( 3)
        8                         12
       12                         8
       2                         3
       3                        2


      mAB mAC
       2 3
       3 2
        1 ABis      toAC
       Triangle is a right angled isosceles
                                              128

6 mat unit 4 coordinate geometry

  • 1.
    Unit 4 CoordinateGeometry Starters  Lesson 1: Midpoint of a line  Lesson 8: Perpendicular and distance between 2 Lines points  Lesson 9: Collinear points  Lesson 2: To find the and drawing lines gradient of a line  Lesson 10:Intercept –  Lesson 3: Gradient of a line intercept method making an angle with the  Lesson 11: Simultaneous axes Equations  Lesson 4: Rearranging the  Lesson 12/13: equation of a straight line Simultaneous Equations-  Lesson 5/6: Finding the Substitution equation of lines from  Lesson 14/15: given information Applications  Lesson 7: Parallel Lines 1
  • 2.
    Co-ordinate Geometry Lesson 1 Midpoint of a line and distance between 2 points 2
  • 3.
    To find themid point of a line Midpoint of a line A line segment is part of a line y 10 The mid point is exactly half way between the end points (x2,y2) 8 ( x1 x2 ) ( y1 y2 ) mp , 2 2 6 ie we average the points 4 In the example 2 x1 , y1 ( 4, 0), x2 , y2 0,8 (x1,y1) –8 –6 –4 –2 x ( x1 x2 ) ( y1 y2 ) mp , –2 2 2 ( 4 0) (0 8) mp , 2 2 mp 2, 4 3
  • 4.
    Midpoint of aLine The midpoint of the line joining two points (x1,y1) and (x2,y2) is . ( x1 x2 ) y1 y2 , 2 2 ( x1 , y1 ) 4
  • 5.
    Be careful whenthere are negatives x1 y1 x2 y2 It is useful to put the correct x1 , y1 (6, 1), x2 , y2 2, 3 coordinate over the top then you ( x1 x2 ) ( y1 y2 ) won’t get mp , confused 2 2 (6 2) ( 1 3) mp , 2 2 (6 2) ( 1 3) mp , 2 2 4 ( 4) mp , 2 2 mp 2, 2 5
  • 6.
    Sometimes you aregiven the midpoint Mid point of AB is (4,5) If A is (2,9) find B A x1 , y1 (2,9), B x2 , y2 ( x, y ), mp 4,5 (2 x) (9 y ) (4,5) , 2 2 (2 x) (9 y ) 4 , 5 2 2 8 2 x, 10 9 y x 6, y 1 B (6,1) 6
  • 7.
    Calculate the midpointof the lines joining the following pairs of points; 1. (9 , 4) and (6 , 2) 2. (3 , 7) and (-4 , -1) 3. (-1 , 5) and (0 , -4) 4. (-5 , 7) and (5 , -7) 5. (-2 , -4) and (3 , -6) 6. (3.7 , -1.8) and (-2.4 , 1.5) 7. (x , 2x) and (-x , -2x) 8. (p , 0) and (-p , -p) 9. (z,- 3 z) and (-z, 3 z) 7
  • 8.
    Ex 2.1: #1a-I(1column) 2-5 WB P170#12-25 (15mins) 8
  • 9.
    Distance between twopoints We can find the distance between two points by Pythagoras y 8 2 2 2 h a b (x2,y2) 7 x 6 2 2 2 d ( x2 x1 ) ( y2 y1 ) 5 (y2-y1) 4 2 2 d ( x2 x1 ) ( y2 y1 ) 3 (x1,y1) x 2 (x2-x1) 1 –8 –7 –6 –5 –4 –3 –2 –1 1 x –1 x1 y1 x2 y2 ( x1 , y1 ) ( 8,2) ( x2 , y2 ) ( 2,6) 9
  • 10.
    Distance between twopoints We can find the distance between two points by Pythagoras 2 2 2 y h a b 8 d2 ( x2 x1 ) 2 ( y2 y1 ) 2 7 (x2,y2) d ( x2 x1 ) 2 ( y2 y1 ) 2 x 6 5 2 2 d ( x2 x1 ) ( y2 y1 ) (y2-y1) 4 d (( 2) ( 8)) 2 (6 2) 2 (x1,y1) 3 x 2 (x2-x1) d ( 2 8) 2 (4) 2 1 x d (6) 2 (4) 2 –8 –7 –6 –5 –4 –3 –2 –1 –1 1 d 36 16 x1 y1 x2 y2 d 52 ( x1 , y1 ) ( 8,2) ( x2 , y2 ) ( 2,6) d 7.2(1dp )units 10
  • 11.
    Calculate the distancebetween the following points; 1. (9 , 4) and (6 , 2) = 3.6 units 2. (3 , 7) and (-4 , -1) = 10.6 units 3. (-1 , 5) and (0 , -4) = 9.1 units 4. (-5 , 7) and (5 , -7) = 17.2 units 5. (-2 , -4) and (3 , -6) = 5.4 units 6. (3.7 , -1.8) and (-2.4 , 1.5) = 6.5 units 7. (x , 2x) and (-x , -2x) 20 x units 8. (p , 0) and (-p , -p) 5 p units 9. (z,- 3 z) and (-z, 3 z) = 4z units 11
  • 12.
    Remember 13 25 5 7 5 3 4 12 24 12
  • 13.
    End of Lesson1 Ex 2.2: #a-j odd, 2,3,4,5,7,8,9 WB P168 #1-11 13
  • 14.
    Lesson 2 To findthe gradient of a line 14
  • 15.
    To find thegradient of a line y Gradient m 10 (x1,y1) y 8 m x 6 ( y2 y1 ) 4 m ( x2 x1 ) 2 –8 –6 –4 –2 x In the example –2 x1 y1 x2 y2 (x2,y2) x1 , y1 ( 4,0), x2 , y2 0,8 (8 0) m (0 ( 4)) 8 m 4 m 2 15
  • 16.
    Be careful whenthere are negatives x1 y1 x2 y2 x1, y1 ( 9, 3), x2 , y2 1, 4 ( y2 y1 ) Sometimes we have unknowns m The gradient of the line between ( x2 x1 ) (4, 2) and ( p,5) is p - 6. Find p (( 4) ( 3)) m (5 2) (( 1) ( 9)) p 6 ( p 4) ( 4 3) m ( p 4)( p 6) 3 ( 1 9) p 2 10 p 24 3 1 m p 2 10 p 21 0 8 ( p 7)( p 3) 0 p 7, p 3 16
  • 17.
    End of Lesson2 WB P174 #26-35 Ex 2.3: # 2-9 17
  • 18.
    Lesson 3 Gradient ofa line making an angle with the axes 18
  • 19.
    To find theGradient of a line making an angle θ with the x axis O y y2 y1 tan Gradient = m A x x2 x1 2– 2 10 8 6 4 –2 O 8 6 4 y2 y1 tan m A tan x2 x1 In the example y x1 y1 x2 y2 10 x1 , y1 ( 4,0), x2 , y2 0,8 (x2,y2) 8 (8 0) 6 Tan (0 ( 4)) 4 O 8 2 Tan (x1,y1) 4 –8 –6 –4 –2 x Tan 2 A –2 Tan 1 (2) 63.4 (1dp ) 19
  • 20.
    eg find theangle 2a line with the gradient of – ¾ 2– 10 8 6 4 2– 2 10 8 6 4 makes with the positive direction of the x axis 3 Tan 10 y 4 8 1 3 tan 6 4 4 36.9 2 36.9 143.1 smallest angle is 36.9° – 2 2 4 6 8 10 x – 2 Largest angle is 36.9 180 143.1 20
  • 21.
    Eg Ex 2.4 1. Calculate the gradient of a line making the following angle with the positive direction of the x-axis a) 240 tan 24 0.4452 gradient b) 1260 tan126 1.376 gradient 3. Calculate angle line makes with positve x axis given gradient is 3 gradient 3 tan 3 Note gradient undefined 1 tan tan 3 1 tan (shift tan 9999999) 60 90 21
  • 22.
    End of Lesson3 Ex 2.4: #1 odd, 2 all, 3 odd, 4 -7 22
  • 23.
    Lesson 4 Rearranging theequation of a straight line 23
  • 24.
    Rearranging the equationof a straight line If a line is written in the form y mx c Gradient y -intercept Eg Ex 2.5 #1 Find the gradient of 2 y 3x 2 0 There are two forms for straight lines We need to make y the subject ax by c 0 2 y 3x 2 0 and 2 y 3x 2 y mx c 2 3 2 y x ( all of both sides by 2) 2 2 2 3 y= x 1 2 3 we can now see the gradient is and the y intercept is -1 2 24
  • 25.
    eg 5 y 3 x 35 0 5y 3 x 35 ( all of both sides by 5) 5 5 5 -3 y x 7 5 -3 we can now see the gradient is and the yintercept is -7 5 From this we can now find the angle the line makes with the x axis 3 tan =- 31 180 5 1 3 149 tan - 5 ( tells us angle angle with Positive direction 30.96 of the x axis going counter clockwise is 1490 ) 31 25
  • 26.
    The other formof the straight line is ax by c o Everything on one side =0 x is positive no fractions Rules to convert y mx c to ax by c 0 get rid of fractions - whole numbers over 1 - bottoms the same - multiply both sides by the bottom put x on the side where it is positive everything else on that side as well, other side =0 26
  • 27.
    Eg x 3 y 4 5 20 5 x 4 3 y 20 5 4 4 5 20 y 5 x 12 20 20 20 20 y 5 x 12 5 x 20 y 12 5 x 20 y 12 27
  • 28.
    End of Lesson4 Ex 2.5: 1k-p, 2-5 Ex 2.6: all 28
  • 29.
    Lesson 5 &6 Finding the equation of lines from given information 29
  • 30.
    Revision Exercise A (2,3), B(-1,4)and 1. a) 3.16 b) 7.28 C(1,-3) form the c) 6.08 vertices of a triangle. 2. a) (0.5 , 3.5) b) (0 , 0.5) c) (1.5 , 0) Find the 1. lengths, 3. a) -0.33 b) -3.5 2. midpoints and 3. gradients of all c) 6 three lines (sides) in the triangle. 30
  • 31.
    Finding the equationof lines from given information y 10 ( y y1 ) ( x2 , y2 ) m 8 ( x x1 ) 6 ( x x1 )m ( y y1 ) 4 ( y y1 ) m( x x1 ) 2– 2 10 10 8 8 6 6 4 4 2– 2 6 6 4 4 ( x1 , y1 ) 2 We can find the equation given –8 –6 –4 –2 x 3 combinations of information 2 –2 1)If we know the gradient (m) and one point (x1,y1) y 10 m 3, point(2,5) 8 ( y y1 ) m( x x1 ) 6 4 ( y 5) 3( x 2) 2 y 5 3x 6 –6 –4 –2 –2 2 4 6 x –4 3x y 1 0 –6 or y 3x 1 –8 – 10 31
  • 32.
    2 eg Find theequation of the line with a gradient of that 5 passes through ( 3,4) 2 m , point(-3,4) 5 ( y y1 ) m( x x1 ) 2 ( y 4) ( x ( 3)) 5 2 14 5 or y x 2 5 5 5 y 4 ( x 3) 5 5y 2 x 14 2 6 y 4 x 5 5 2 x 5 y 14 0 2 14 y x 5 5 32
  • 33.
    2) If youare given two points then you can find the gradient first, then do as 1 above x1 y1 x2y2 eg Find the equation of the line that passes through (4,1) and (7,3) y2 y1 3 1 2 m m m eg(7,3) x2 x1 7 4 3 First find ( y y) m( x Then the either x1 ) using point and or (4,1) ( y y1 ) m( x x1 ) 2 gradient ( y 3) ( x y7) y1 m( x x1 ) 2 3 ( y 1) ( x 4) 2 14 3 y 3 x 2 8 3 3 y 1 x 2 5 3 2 5 3 3 y x or y x 3 3 2 5 3 3 3 y x 3y 2x 5 3 3 2x 3y 5 0 We would get the same answer if we used either point 33
  • 34.
    3) A (2,3),B(-1,4) and C(1,-3) form the vertices of a triangle. Find the equations of all three lines in the triangle. 34
  • 35.
    4) If weare given the angle with the x axis and a point. This is similar to being given the gradient (Extn) Eg A line passes through (3,4) and makes an angle of 63.4 with the positive direction of the x axis ( y y1 ) m( x x1 ) tan 63.4 m y 4 2( x 3) m 2 y 4 2x 6 y 2x 2 2x y 2 0 Summary: We can find the equation of a straight line given 1) gradient (m) and one point ( x1 , y1 ) 2) two points, then you can find the gradient first, then do as 1 above 3) the angle with the x axis and a point. 35
  • 36.
    End of Lesson5 & 6 Ex 2.7: all WB P178 #36-51 Ex 2.8: 1h,I,j, 2all, 3-6 Ex 2.9: all 36
  • 37.
  • 38.
    Parallel Lines Parallel Lines Are always the same distance apart Never meet If a line is written in the form y mx c 2– 2 10 10 8 8 6 6 4 4 2– 2 10 10 8 8 6 6 4 4 We can see Gradient y -intercept If lines have the same gradient then they are parallel y 10 y 2 x 6 is parallel to y 2x 1 8 6 4 2 Any line with a gradient – 10 – 8 – 6 – 4 – 2 2 4 6 8 10 x of 2 will be parallel to these – 2 – 4 – 6 – 8 – 10 38
  • 39.
    If lines twolines y m1 x c and y m2 x c are parallel then m1 m2 Eg Find the line through (5,7) parallel to 3 y 4x 5 0 First make y the subject so line is in the form of y mx c. Then we can see the gradient 3y 4x 5 0 4 ( y 7) ( x 5) 3 3y 4x 5 4 20 4 5 y 7 x y x 3 3 3 3 4 41 y x 4 3 3 m 3 4 41 3 or y x then using point(5,7) 3 3 3 and 3y 4 x 41 (y y1 ) m( x x1 ) 3 y 4 x 41 0 39
  • 40.
    If a linethrough (3,4) and (6,a) is parallel to 4 x 2 y 5 0 Find "a" If lines are parallel then they must have the same gradient ( y2 y1 ) m , 4x 2 y 5 0 ( x2 x1 ) 2y 4x 5 The gradient of the two 5 points will be the same y 2x 2 (a 4) m 2 2 (6 3) a 4 2 3 6 a 4 a 10 40
  • 41.
    End of Lesson7 Ex 2.10: 2-7 41
  • 42.
  • 43.
    Perpendicular Lines 2– 2 10 10 8 8 6 6 4 4 2– 2 10 10 8 8 6 6 4 4 Perpendicular means: at right angles to If lines are perpendicular then they are at right angles to each other We know -ve y 2x 4 +ve y 10 8 We can see these 6 lines are not 4 perpendicular 2 – 10 – 8 –6 –4 –2 2 4 6 8 10 x –2 –4 –6 –8 y 2x 1 – 10 43
  • 44.
    If two linesy m1 x c and y m2 x c are perpendicular then m1 m2 2– 2 10 10 8 8 6 6 4 4 2– 2 10 10 8 8 6 6 4 4 1 1 1 ie m1 and m2 m2 m1 y 2x 6 y The gradients are negative reciprocals of each other yy 10 We can see these two 8 lines are perpendicular 6 4 Consider gradients of 2 x – 10 –8 –6 –4 –2 2 4 6 8 10 xx 1 –2 m 2 and m - 2 –4 –6 1 y x 3 –8 2 – 10 44
  • 45.
    Egs Ex 2.11 Find the gradient perpendicular to 3 -1 gradient is 3 7 Find the gradient perpendicular to 2 -2 gradient is 7 Find the gradient perpendicular to p -1 gradient is p 45
  • 46.
    A (2,3), B(-1,4)and C(1,-3) form the vertices of a triangle. Find the equations of the perpendicular bisectors of all three lines 46
  • 47.
    Egs Ex 2.11 EgFind equation of a line through (-2,3) perpendicular to 3 y 4x 7 0 3y 4x 7 3 6 y 3 x 4 7 4 4 y x 4 3 3 m 3 3 3 y x 4 2 3 gradient 4 3 3 2 4 or y x equation of perpendicular line is 4 4 2 2 (y y) m( x x1 ) 4y 3x 6 3 3x 4 y 6 0 ( y 3) ( x ( 2)) 4 3 y 3 ( x 2) 4 47
  • 48.
    End of Lesson8 Ex 2.11:#1-3,5-10 Extn 11-13 WB p182 # 52-59 48
  • 49.
    Lesson 9 Collinear pointsand Drawing lines 49
  • 50.
    Collinear points andDrawing lines y 6 C Collinear Points 4 (2,4) Ie points on the same line 2 If points are on the same line, any two –6 –4 –2 x should give the same gradient 2 4 6 –2 B (0,-2) –4 –6 y y1 –8 using m A x x1 (-3,-11) – 10 – 12 ( 2 ( 11)) ( 4 ( 11)) ( 4 ( 2)) mAB mAC mBC (0 ( 3)) (2 ( 3)) (2 (0)) 6 9 15 2 3 5 3 3 3 gradient of AB = gradient of AC = gradient of BC 50 So these points are collinear
  • 51.
    NOTE: if pointsare collinear ie on the same line we can solve for an unknown (2,1),( 3, q),(1, 2)are colinear so all points must meet the same equation and have the same gradient ( y2 y1 ) ( y y1 ) m( x x1 ) m , ( x2 x1 ) The gradient of any two point will be the same ( 2 1) ( 2 (q)) 2 q m m 3 (1 2) (1 ( 3)) 4 2 q 2 q 12 3 m m 1 3 q 14 1 2 q q 14 m 3 m 4 As points are collinear these gradients must be equal 51
  • 52.
    Drawing lines: To drawlines we need two pieces of information 1) 2 points- plot and join 2) 1 point and the gradient-plot point and use gradient to find others 3) equation – either sub in x=1,2,3 etc -or use gradient intercept - or use intercept-intercept method For Ex 2.13 we will rearrange in the form of y=mx+c to establish the gradient and y intercept 52
  • 53.
    End of Lesson9 Ex2.12: all Drawing Lines: Ex 2.13 odd WB P186 #64-75 WB P187 #76-81 53
  • 54.
    Lesson 10 Intercept –intercept method 54
  • 55.
    Intercept – interceptmethod 1– 1 4 3 2 2 1– 1 6 5 4 3 2 2 If given the line in the form ax by c 0 it is easier to plot using this method To find x intercept, put y = 0 Remember equation of x axis is y = 0 To find y intercept, put x = 0 equation of y axis is x = 0 y Eg. 2x 3y 6 4 1)Cuts y axis put x 0 3 2(0) 3 y 6 2 3y 6 y 2 1 This gives us (0,2) 2)Cuts x axis put y 0 – 2 – 1 1 2 3 4 5 6 x 2 x 3(0) 6 –1 2x 6 –2 x 3 This gives us (3,0) 55
  • 56.
    y 4 If given the graph 3 We can read the equation of the graph 2 1) gradient intercept method 1 2 y x 2 3 –2 –1 1 2 3 4 5 6 x –1 2) Find gradient –2 y2 y1 m Use gradient and point (3,0) x2 x1 3 2 3 (0 2) ( y y) m( x x1 ) or y x 2 m 3 3 3 (3 0) 2 ( y 0) ( x 3) 3y 2x 6 2 3 m 2 2x 3y 6 0 3 y x 2 3 56
  • 57.
    End of Lesson10 Ex 2.14all Ex 2.15 all 57
  • 58.
  • 59.
    Simultaneous Equations Simultaneous equationsrepresent 2 lines on a graph that may intersect We have three methods of finding the point of intersection 1) Graphing- either plot or use calculator 2) Elimination 3) Substitution (covered tomorrow) 59
  • 60.
    2)Elimination Line up equationsx over x y over y Sometimes we may need to rearrange to do this Decide what to eliminate. i.e. what number is, or can we get, the same Do we need to add or subtract to eliminate? 7x y 1 1 7x y 1 4x 3y 3 4x 3y 3 2 7(0) y 1 4(0) 3( 1) 3 3 (7 x y 1) Multiply y 1 equation 1 Correct by 3 to make the y 4 x 3 y First write out Now ytheysame are the Sub y=-1 3 termthe 1 terms equations across same but have opposite back into the 21x 3 y 3 the page signs so we can add second 4x 3y 3 Sub x=0 back equation to 25 x 0 into equation Lines intersect at (0, 1) check 1 x 0 60
  • 61.
    Examples 3 y x 5 and y 2x 6 4 4 y 3x 25 2 y 5x 7 On Graphics Calculator either; • Graph equations then - G-solve, intersect, Answer (4,2) • Solve Simultaneous Equations in Equation Mode * 61
  • 62.
    4x 7 y 20 10 x 5 y 25 * 62
  • 63.
    Ex 2.18 #2 4x 2 3y 8 5 2 x 1 y 2 4 2 3 63
  • 64.
    End of Lesson11 Ex 2.17:1-17 odd Ex 2.18 1-5 Extn all 64
  • 65.
    Lesson 12 &13 Simultaneous Equations - Substitution 65
  • 66.
    Simultaneous Equations 3) Substitution Ifwe know what x or y is, then in the second equation, we can put what x or y is instead of writing x or y. Hence we have the whole equation with only one variable. Eg. y 5 4 x, 1 y 5 4 x, 10 x 7 y 1 10 x 7 y 1 2 y 5 4(2) 10(2) 7( 3) 1 10 x 7(5 4 x) 1 y 3 20 21 1 Sub First write out Correct 10 x 35 28x equations acrossinto 2 1 1 the Now we can sub y=-3 into the 18x 36 It is sensible to page. second equation write the y= equation x 2 first to check Now we sub x=2 back Point of intersection (2,-3) into the first equation 66
  • 67.
    Example y x 4 3x 2 y 2 0 * 67
  • 68.
    Example y 3x 9 4 x y 13 * 68
  • 69.
    Example y 2x 3 y x 9 * 69
  • 70.
    Example y 3x 1 y 3x 5 Lines have the same gradient They are parallel. No solution possible * 70
  • 71.
    End of Lesson12 & 13 Ex 2.19 #1-15 odd Extn 16-18 Applications: Extra sheet Ex 5.5 1-14 Extn all 71
  • 72.
    Lesson 14 &15 Applications of Simultaneous Equations 72
  • 73.
    End of Lesson14 & 15 Applications: Ex 2.20: 1-15 Extn all Ex 16.17 sheet RUR Q Merit & Excellence Questions WB P 192 #1-7 RUR Q Exam Excellence Q 2.4 W/S 73
  • 74.
    Starters  Lesson 1  Lesson 9  Lesson 2  Lesson 10  Lesson 3  Lesson 11  Lesson 4  Lesson 12  Lesson 5  Lesson 13  Lesson 6  Lesson 14  Lesson 7  Lesson 15  Lesson 8 74
  • 75.
    Starter Lesson 1 Find the equation and list features y 10 9 8 7 6 5 4 3 2 1 – 5 – 4 – 3 – 2 – 1 1 2 3 4 5 x – 1 – 2 – 3 – 4 – 5 – 6 – 7 – 8 – 9 – 10 75
  • 76.
    Answers Starter Lesson1 y 10 9 8 7 6 5 4 3 2 1 – 5 – 4 – 3 – 2 – 1 – 1 1 2 3 4 5 x – 2 – 3 – 4 – 5 – 6 – 7 – 8 – 9 – 10 y k ( x 1)( x 3)( x 5) (0,-5) Sub in (0, 5) 5 k ( 1)(3)(5) 1 5 15k y ( x 1)( x 3)( x 5) 3 1 k 3 76
  • 77.
    y Starter Lesson 2 10 9 8 7 6 5 1) Find the equation 4 3 and list features 2 1 – 5 – 4 – 3 – 2 – 1 – 1 1 2 3 4 5 x – 2 – 3 – 4 – 5 – 6 – 7 – 8 – 9 – 10 2) Find the midpoint of A(-2,-5) B(3,1) and the distance between the two points 3) Sketch the graph of y 2 x 1, x 3 77
  • 78.
    1) 10 9 y Answers Lesson 2 8 7 6 5 4 3 2 1 – 5 – 4 – 3 – 2 – 1 – 1 1 2 3 4 5 x – 2 – 3 – 4 – 5 – 6 – 7 – 8 – 9 – 10 y k ( x 2)( x 1)( x 5) (0,-4) Sub in (0, 4) 4 k ( 2)(1)(5) 2 4 10k y ( x 2)( x 1)( x 5) 5 2 k 5 78
  • 79.
    Answers Lesson 2 2) A( 2, 5), B (3,1) x1 x2 y1 y2 d ( x2 x1 ) 2 ( y2 y1 ) 2 mp , 2 2 ((3) ( 2)) 2 ((1) ( 5)) 2 2 3 5 1 , (3 2) 2 (1 5) 2 2 2 1 4 (5) 2 (6) 2 , 2 2 25 36 1 61 , 2 2 7.8(1dp) 79
  • 80.
    Answers Lesson 2 y 8 7 6 5 4 3 2 1 – 3 – 2 – 1 1 2 3 4 5 6 x – 1 – 2 – 3 – 4 – 5 y 2 x 1, x 3 We have a hole at x=3 80
  • 81.
    Starter Lesson 3 1) Accurately sketch the graph 2x 1 y x 5 That means properly 1) Cuts x axis y 0 2) Cuts y axis x 0 3)Vertical asymptote y 4) Horizontal asymptote x 2) What transformation maps y x2 9 onto y 9 x2 3) Sketch the graph of y 3x 5, x 2 81
  • 82.
    Q1) y 1) Cuts x axis y 0 15 2x 1 14 13 y 2x 1 0 12 11 x 5 10 9 2x 1 8 7 6 5 1 4 x 3 2 2 1 x – 15– 14– 13– 12– 11– 10 – 9 – 8 – 7 – 6 – 5 – 4 – 3 – 2 ––11 1 2 3 4 5 – 2 2) Cuts y axis x 0 – 3 – 4 – 5 2(0) 1 – 6 – 7 y – 8 – 9 (0) 5 – 10 1 y 4) Horizontal asymptote x 5 2 1 2x x 1 x 3)Vertical asymptote y y y x 5 5 x x x 5 0 2 2 x 5 y y 1 y 2 y 2 82
  • 83.
    2) y 10 9 8 7 6 5 4 y x2 9 3 2 1 – 10 – 9 – 8 – 7 – 6 – 5 – 4 – 3 – 2 ––11 1 2 3 4 5 6 7 8 9 10 x – 2 – 3 – 4 – 5 – 6 – 7 y 9 x2 – 8 – 9 – 10 Reflection in the x axis 83
  • 84.
    y 10 9 8 7 6 5 4 3 2 1 – 5 – 4 – 3 – 2 – 1 – 1 1 2 3 4 5 x – 2 – 3 – 4 – 5 – 6 – 7 – 8 – 9 – 10 – 11 – 12 – 13 – 14 – 15 y 3x 5, x 2 We have a hole at x = -2 84
  • 85.
    Starter Lesson 4 1)Accurately sketch the graph x 3 That means properly y x 4 1) Cuts x axis y 0 2) Cuts y axis x 0 3)Vertical asymptote y 4) Horizontal asymptote x 2) What transformation maps y ( x 2)2 onto y ( x 2)2 3 3) Sketch the graph of y x 4, x 1 4 85
  • 86.
    Q1) y 15 x 3 14 13 y 1) Cuts x axis y 0 12 11 x 4 10 9 x 3 0 8 7 6 x 3 5 4 3 2 2) Cuts y axis x 0 1 x – 15– 14– 13– 12– 11– 10 – 9 – 8 – 7 – 6 – 5 – 4 – 3 – 2 ––11 1 2 3 4 5 – 2 (0) 3 – 3 – 4 y – 5 (0) 4 – 6 – 7 – 8 – 9 3 – 10 y 4 4) Horizontal asymptote x x 3 3 x x 3)Vertical asymptote y y y x 4 4 x x x 4 0 1 x 4 y y 1 y 1 y 1 86
  • 87.
    2) y 10 9 8 7 y ( x 2) 2 6 5 4 3 2 1 –5 –4 –3 –2 – 1– 1 1 2 3 4 5 6 7 8 x –2 –3 –4 –5 –6 –7 y ( x 2) 2 –8 –9 – 10 Reflection in the x axis 87
  • 88.
    y 3 2 1 – 5 – 4 – 3 – 2 – 1 1 2 3 4 5 x – 1 – 2 – 3 – 4 – 5 – 6 – 7 – 8 – 9 – 10 3 We have a hole at x = 1 y x 4, x 1 4 88
  • 89.
    Starter Lesson 5 1)Accurately sketch the graph 2x 1 That means properly y 1) Cuts x axis y 0 x 4 2) Cuts y axis x 0 3)Vertical asymptote y 4) Horizontal asymptote x List Features 2) Sketch the graph of y ( x 1)(3 x)( x 2) 89
  • 90.
    Q1) y 1) Cuts x axis y 0 15 2x 1 14 13 y 2x 1 0 12 11 x 4 10 9 2x 1 8 7 6 5 1 4 x 3 2 2 1 – 15– 14– 13– 12– 11– 10 – 9 – 8 – 7 – 6 – 5 – 4 – 3 – 2 ––11 1 2 3 4 5 x 2) Cuts y axis x 0 – 2 – 3 – 4 – 5 2(0) 1 – 6 – 7 y – 8 (0) 4 – 9 – 10 1 y 4) Horizontal asymptote x 4 2x 1 2 1 x x y y x 4 3)Vertical asymptote y 4 x x x 4 0 2 2 y y x 4 1 y 2 y 2 90
  • 91.
    Features 1 x intercept x 2 1 y intercept y 4 Vertical asymptote x 4 Horizontal asymptote y 2 fundemental discontinuity at x -4 point symmetry at (-4,2) axis of symmetry y x 6, y x 2 x ,y 2 x ,y 2 91
  • 92.
    y 8 7 6 5 4 3 2 1 – 5 – 4 – 3 – 2 – 1 1 2 3 4 5 x – 1 – 2 – 3 – 4 – 5 – 6 – 7 – 8 – 9 – 10 y ( x 1)(3 x)( x 2) 92
  • 93.
    Starter Lesson 6 1)Accurately sketch the graph 3x 4 That means properly y 1) Cuts x axis y 0 x 2 2) Cuts y axis x 0 3)Vertical asymptote y 4) Horizontal asymptote x List Features 2) Sketch the graph of x 2 ( y 1) 2 25 List Features 93
  • 94.
    Q1) y 15 3x 4 1) Cuts x axis y 0 14 13 y 12 11 x 2 3x 4 0 10 9 8 3x 4 7 6 5 4 4 3 2 x 1 3 – 10 – 9 – 8 – 7 – 6 – 5 – 4 – 3 – 2 ––11 –2 1 2 3 4 5 6 7 8 9 10 x –3 2) Cuts y axis x 0 –4 –5 –6 3(0) 4 –7 –8 y –9 – 10 (0) 2 y 2 4) Horizontal asymptote x 3x 4 3 4 x x y y x 2 3)Vertical asymptote y 2 x x x 2 0 3 3 y y x 2 1 y 3 y 3 94
  • 95.
    Features 4 x intercept x 3 y intercept y 2 Vertical asymptote x 2 Horizontal asymptote y 3 fundemental discontinuity at x -2 point symmetry at (-2,3) axis of symmetry y x 5, y x 1 x ,y 3 x ,y 3 95
  • 96.
    y 6 x2 ( y 1) 2 25 5 4 3 Centre(0,1) 2 Radius =5units 1 Y intercepts (0,6)and(0,- –5 –4 –3 –2 –1 1 2 3 4 5 x –1 4) –2 Max(0,6), Min(0,-4) –3 –4 –5 0 x2 y2 25 translated by 1 96
  • 97.
    Q1) Starter Lesson 7 Find the equation, and list features y 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 –5 –4 –3 –2 –1 1 2 3 4 5 6 7 8 9 10 x – 1 – 2 – 3 – 4 – 5 97
  • 98.
    Features x intercept x 4.6 2 y intercept y 7 3 Vertical asymptote x 3 Horizontal asymptote y 5 fundemental discontinuity at x 3 point symmetry at (3,5) axis of symmetry y x 2, y x 8 x ,y 3 x ,y 3 98
  • 99.
    2)What transformation willmap x2 y2 1 on to the graph x 2 y 2 16 y 5 4 3 2 1 –5 –4 –3 –2 –1 1 2 3 4 5 x –1 –2 –3 –4 –5 99
  • 100.
    Image radius SF Object radius 4 SF 1 SF 4 Enlargement about (0,0) of scale factor 4 Must have centre 100
  • 101.
    3) What transformationmaps y x 2 on to y ( x 3)2 5 y 8 7 Translation by 6 5 3 the vector 4 -5 3 2 1 –5 –4 –3 –2 –1 1 2 3 4 5 6 7 x –1 –2 –3 –4 –5 –6 101
  • 102.
    Starter Lesson 8 1)Prove that A(-4,-4), B(1,6), C(11,1) form a right angled isosceles triangle 102
  • 103.
    1– 1 10 10 99 8 8 7 7 6 6 5 5 4 4 3 3 2 2 1– 1 12 11 10 9 8 8 7 7 6 6 5 5 4 4 3 3 2 2 1) Prove that A(-4,-4), B(1,6), C(11,1) form a right angled isosceles triangle y 10 9 8 7 (1,6) 6 5 B 4 3 C (11,1) 2 1 –8 –7 –6 –5 –4 –3 –2 ––1 1 1 2 3 4 5 6 7 8 9 10 11 12 x –2 –3 –4 A –5 –6 (-4.-4) –7 –8 –9 – 10 103
  • 104.
    y y1 A( 4,4), B(1,6), C (11,1) m y x x1 10 6 ( 4) 9 (1,6) mAB 8 7 1 ( 4) 6 B 5 10 4 3 2 5 1 (11,1) 2 –8 –7 –6 –5 –4 –3 –2 ––1 1 1 2 3 4 5 6 7 8 9 10 11 12 x C –2 –3 –4 A –5 –6 1 6 (-4.-4) –7 mBC –8 11 1 –9 – 10 5 10 1 2 1 as gradients multiply to give -1 1 2 2 they are at right angles 104
  • 105.
    d AB ( x x1 ) 2 ( y y1 ) 2 d AC ( x x1 ) 2 ( y y1 ) 2 d AB ( 4 1) 2 ( 4 6) 2 d AC ( 4 11) 2 ( 4 1) 2 d AB ( 5) 2 ( 10) 2 d AC ( 15) 2 ( 5) 2 d AB 25 100 d AC 225 25 d AB 125 d AC 250 Because 2 sides are equal and one d BC ( x x1 ) 2 ( y y1 ) 2 is not equal, therefore the triangle is d BC (1 11) 2 (6 1) 2 isosceles d BC ( 10) 2 (5) 2 We proved before that AB is Perpendicular to BC so this is a right d BC 100 25 angled isosceles triangle d BC 125 105
  • 106.
    Starter Lesson 9 1)Find the equation of the line through (9,1) and (4,7) 2)Find the equation of the line through (3,2) and (3,10) 106
  • 107.
    1)Find the equationof the line through (9,1) and (4,7) y2 y1 Equation m y y1 m( x x1 ) x2 x1 7 1 6 m y 1 ( x 9) 4 9 5 6 6 54 m y 1 x 5 5 5 6 59 y x 5 5 5y 6 x 59 0 107
  • 108.
    2)Find the equationof the line through (3,2) and (3,10) y2 y1 m x2 x1 10 2 m 3 3 m undefined We know lines with an undefined gradient arevertical and so x In this case x 3 108
  • 109.
    Starter Lesson 10 1)Find the line through the point (5,4) parallel to the line 3x y 2 0 3 2)Draw the lines y x 5 4 4 y x 2 3 3)Prove the above lines are perpendicular 109
  • 110.
    1) Find theline through the point (5,4) parallel to the line 3x y 2 0 y 3x 2 gdt 3 pt (5, 4) y y1 m( x x1 ) y 4 3( x 5) y 4 3x 15 y 3x 11 110
  • 111.
    3 2)Draw the linesy x5 4 4 y x 2 3 3)Prove the above lines are perpendicula r y 5 3 4 4 1 3 4 3 2 As gradients multiply to = -1 1 Lines are perpendicular –5 –4 –3 –2 –1 1 2 3 4 5 x –1 –2 –3 –4 –5 111
  • 112.
    Starter Lesson 11 1)Find the equation of the line that passes through (1,8) and (6,8) 2) Use the intercept- intercept method to plot 6x 4 y 3 3) Find the line through the point (1,4) perpendicular to the line 4 x y 3 0 112
  • 113.
    1) Find theequation of the line that passes through (1,8) and (6,8) y2 y1 m x2 x1 8 8 m Line has a gradient of zero so horizontal 6 1 0 y ? m 5 both y coordinates are 8 m 0 y 8 113
  • 114.
    2) Use theintercept- intercept method to plot 6x 4 y 3 y Cuts x axis y 0 5 6 x 4(0) 3 4 3 6x 3 2 3 x 6 1 1 x x –5 –4 –3 –2 –1 1 2 3 4 5 2 –1 Cuts y axis x 0 –2 6(0) 4 y 3 –3 4y 3 –4 3 –5 y 4 114
  • 115.
    3) Find theline through the point (1,4) perpendicular to the line 4 x y 3 0 1 m (1, 4) 4x 3 y 4 y 4x 3 y y1 m( x x1 ) m 4 1 y 4 ( x 1) 1 4 m 1 1 4 y 4 x 4 4 1 1 16 y x 4 4 4 1 17 y x 4 4 x 4 y 17 0 115
  • 116.
    Lesson 12 Starter 1)Solve 2y x 2 5 x 2 y 10 0 3x 1 2) Sketch y x 2 and list features That means properly 1) Cuts x axis y 0 2) Cuts y axis x 0 3)Vertical asymptote y 4) Horizontal asymptote x 116
  • 117.
    1) Solve 2y x 2 5 x 2 y 10 0 2y x 2 5 x 2 y 10 0 5(3) 2 y 10 0 2(2.5) 3 2 15 2 y 10 0 5 3 2 x 2y 2 5 2y true 5 x 2 y 10 y 2.5 4 x 12 (3, 2.5) x 3 Checked on the calculator of course 117
  • 118.
    3x 1 y 3x 1 2) Sketch y and list features 15 14 y x 2 13 12 x 2 11 1) Cuts x axis y 0 10 9 8 7 3x 1 0 6 5 4 3x 1 3 2 1 1 – 15– 14– 13– 12– 11– 10 – 9 – 8 – 7 – 6 – 5 – 4 – 3 – 2 ––11 – 2 1 2 3 4 5 x x – 3 – 4 3 – 5 – 6 – 7 2) Cuts y axis x 0 – 8 – 9 – 10 3(0) 1 y (0) 2 4) Horizontal asymptote x 3x 1 1 3 1 x x y y y x 2 2 2 x x 3)Vertical asymptote y 3 3 y y x 2 0 1 x 2 y 3 y 3 118
  • 119.
    Features 1 x intercept x 3 1 y intercept y 2 Vertical asymptote x 2 Horizontal asymptote y 3 fundamental discontinuity at x 2 point symmetry at (-2,3) axis of symmetry y x 5, y x 1 x ,y 3 x ,y 3 119
  • 120.
    Starter Lesson 13 1)Find the line perpendicular to 5 y 4 x 7 0 which passes through the point (3,1) 2) If (3,4) (6,2) (8,a) are collinear Find a 120
  • 121.
    1) Find theline perpendicular to 5 y 4 x 7 0 which passes through the point (3,1) 5y -4 x 7 4 7 y x 5 5 4 5 m ,m 5 4 y y1 m( x x1 ) 5 y 1 ( x 3) 4 5 11 y x 4 4 5 x 4 y 11 0 121
  • 122.
    2) If (3,4)(6,2) (8,a) are collinear Find a y2 y1 m if lines are collinear they have the same gdt x2 x1 2 4 2 a 2 m 6 3 3 8 6 2 2 2 a 2 3 m 3 2 3 2 2 4 3(a 2) 4 3a 6 2 3a 2 a 3 122
  • 123.
    Starter Lesson 14 1)Showthat the line through (0,4) and (4,1) is perpendicular to the line through (3,6) and (-3,-2) 2)Find the midpoint of A(4,2) and B(10,10) 123
  • 124.
    1)Show that theline through A(0,4) and B(4,1) is perpendicular to the line through C(3,6) and D(-3,-2) y2 y1 y2 y1 mAB mCD x2 x1 x2 x1 1 4 2 6 mAB mCD 4 0 3 3 3 8 mAB mCD 4 6 4 mCD 3 as mAB mCD 1 3 4 1 lines are perpendicular 4 3 124
  • 125.
    2)Find the midpointof A(4,2) and B(10,10) ( x1 x2 ) ( y1 y2 ) m , 2 2 (4 10) (2 10) m , 2 2 14 12 m , 2 2 m 7, 6 125
  • 126.
    Starter Lesson 15 Provethat the points A(-3,7) B(9,15) C(5,-5) form a right angled isosceles triangle 126
  • 127.
    Prove that thepoints A(-3,7) B(9,15) C(5,-5) d AB ( x2 x1 ) 2 ( y2 y1 ) 2 form a right angled isosceles triangle d (9 ( 3)) 2 (15 7) 2 y d 122 82 18 17 d 208 16 15 B d AC ( x2 x1 ) 2 ( y2 y1 ) 2 14 13 12 d (5 ( 3)) 2 ( 5 7) 2 11 10 d 82 122 9 8 A 7 d 208 6 5 d BC ( x2 x1 ) 2 ( y2 y1 ) 2 4 3 2 d (9 5) 2 (15 ( 5) 2 1 – 5 – 4 – 3 – 2 – –1 1 1 2 3 4 5 6 7 8 9 10 x d 42 202 –2 –3 d 416 –4 –5 –6 C As two sides are the same and one is different, –7 –8 this proves that the triangle is isosceles 127
  • 128.
    y2 y1 y2 y1 mAB mAC x2 x1 x2 x1 15 7 5 7 9 ( 3) 5 ( 3) 8 12 12 8 2 3 3 2 mAB mAC 2 3 3 2 1 ABis toAC Triangle is a right angled isosceles 128