Upcoming SlideShare
×

Coordinate geometry

34,759 views

Published on

hi(: Bored at home so did this. enjoy^^

38 Likes
Statistics
Notes
• Full Name
Comment goes here.

Are you sure you want to Yes No
• @Waleed Yahya I know that you asked your question 1 year ago but I thought that if you still don't know the answer it's better to know it. the answer of your question is a line. you should draw line y=14-5x and all points on this line is your answer. If you have further question your most welcome to ask me by email. alborzi_edu@yahoo.com

Are you sure you want to  Yes  No

Are you sure you want to  Yes  No

Are you sure you want to  Yes  No
• can i get the answer for 5x+y=14
plz my maths exam is in two days and this question came from my book but i cant understand it

Are you sure you want to  Yes  No
• i like the consistency of the slides, i think it's for the students to grasp this. To the author: 'would you mind to share your slide for us?' Thank you..

Are you sure you want to  Yes  No
Views
Total views
34,759
On SlideShare
0
From Embeds
0
Number of Embeds
1,533
Actions
Shares
0
0
6
Likes
38
Embeds 0
No embeds

No notes for slide

Coordinate geometry

1. 2. Content Page <ul><li>Elementary / Additional Math </li></ul><ul><li>Distance Of A Line </li></ul><ul><li>Midpoint Of A Line </li></ul><ul><li>Equation Of A Straight Line </li></ul><ul><li>Parallel Lines </li></ul><ul><li>Parallelogram </li></ul><ul><li>Rhombus And Square </li></ul><ul><li>Additional Math </li></ul><ul><li>Perpendicular Line </li></ul><ul><li>Perpendicular Distance </li></ul><ul><li>Perpendicular Bisector </li></ul><ul><li>Solving For Intersection Points </li></ul><ul><li>Area Of A Polygon </li></ul>
2. 3. y-intercept (x = 0) x-intercept (y = 0) Compare Line PQ and AB. Which line is steeper? The gradient is a value that tells us about the steepness of a line X = midpoint If AB = 10 cm and AX = 5 cm, then X is the midpoint of AB A B X P Q y x
3. 4. Distance between two points A( x 1 , y 1 ) and B( x 2 , y 2 ) : AB = The Distance Formula B ( x 2 , y 2 ) A ( x 1 , y 1 )
4. 5. Example Find the length of AB if A = (- 4,3) and B = (6, 8). Distance formula = AB
5. 6. The Midpoint Formula Coordinates of the midpoint (X) of two points A( x 1 , y 1 ) and B( x 2 , y 2 ) : X =
6. 7. Example Find the coordinates of the midpoint of AB if A = (- 1, 8) and B = (2, - 5). Midpoint Formula Midpoint Of AB
7. 8. Gradient of a Straight Line The GRADIENT (m) is a value that tells us about the steepness of a line The gradient (m) of a line AB where A = ( x 1 , y 1 ) and B = ( x 2 , y 2 ) : m =
8. 9. Gradient is positive i.e. m > 0 Gradient is negative i.e. m < 0 I am running down a slope, it’s so easy! LEFT RIGHT LEFT RIGHT I am running up a slope, how tiring!
9. 10. Gradient is zero. i.e. m = 0 Gradient is infinity for a vertical line. i.e. m = ∞ LEFT RIGHT This is a level road! It’s impossible to run up this! It’s so steep!
10. 11. Equation of a Straight Line y = m x + c First Method gradient y-intercept
11. 12. We must find gradient (m) and y-intercept (c) (Substitute into formula y = m x + c ) (To find c, we can either substitute coordinates of A or B into above) Example Find the equation of line AB if A is (2, 5) and B is (-1, 6). Hence, equation of AB :
12. 13. y – y 1 = m ( x – x 1 ) Second Method gradient
13. 14. Example Find the equation of line AB if A is (2, 5) and B is (-1, 6). After finding the gradient, we can use the formula straight away. Equation of AB :
14. 15. <ul><li>Q1) The coordinates of the points A, B and C are (-7, 1), (3, 6) and (0, 2) respectively. </li></ul><ul><li>Find the gradient of BC. </li></ul><ul><li>Write down the equation of the line BC. </li></ul><ul><li>Given that B is the mid-point of the line AX, find the coordinates of X. </li></ul>TRY THIS QUESTION NOW…
15. 16. Parallel Lines Gradient of AB = Gradient of CD m 1 = m 2 A B C D
16. 17. If ABCD is a rectangle/ square rhombus or //gram, then X is the midpoint of BD and AC Rectangle/Square/ Rhombus/Parallelogram A D C B X midpoint
17. 18. If ABCD is a rhombus/square, then the diagonals will be perpendicular to each other. Rhombus/Square A B C D A D C B
18. 19. Example The line 3x + 7y = 13 is parallel to the line kx + 8 = 3y. Find the value of k. 3x + 7y = 13 and kx + 8 = 3y share the same gradient.
19. 20. Example The equation of a straight line l is 5x + 6y + 30 = 0. K is the point (3, -1). a) Find the coordinates of the point where the line l crosses the x-axis ; When l crosses the x-axis, y = 0. Substitute into equation.
20. 21. b) Find the coordinates of the point M, at which the line l intersects the line x = 2 ; Example The equation of a straight line l is 5x + 6y + 30 = 0. K is the point (3, -1). When l crosses x = 2, we can find M by substituting x = 2 into equation. x = 2
21. 22. c) Find the equation of the line passing through K and parallel to l ; The line shares the same gradient as the line l . Since the line passes through K, we can substitute K(3, -1) to find the equation. Example The equation of a straight line l is 5x + 6y + 30 = 0. K is the point (3, -1).
22. 23. d) Find the equation of the line passing through K and parallel to the line 5y – 10 = 0 ; The line shares the same gradient as the line 5y – 10 = 0. This is a vertical line. Gradient = infinity Since the required line is parallel to this line, it is a vertical line too. Since it passes through K, its equation should be Example The equation of a straight line l is 5x + 6y + 30 = 0. K is the point (3, -1).
23. 24. Q1a) Find the gradient of the straight line 5x + y = 14. b) The point (p, 2p) lies on the straight line x + 4y = 36. Calculate the value of p. TRY THESE QUESTIONS NOW… <ul><li>Q2) The equation of the line l is 2y - x = 10. Find </li></ul><ul><ul><li>the coordinates of the point where l intersects the y-axis; </li></ul></ul><ul><ul><li>the gradient of l; </li></ul></ul><ul><ul><li>the equation of the line which is parallel to l and which passes through the point (0, -3); </li></ul></ul><ul><ul><li>the x-coordinate of the point where l intersects the line y = 3x. </li></ul></ul>
24. 25. Perpendicular Lines (Gradient of AB) x (Gradient of CD) = -1 (m 1 )(m 2 ) = -1 A B C D
25. 26. Perpendicular Distance Perpendicular Distance = CX Foot of the perpendicular from Point C = X X A B C
26. 27. Example 1 If the line PQ is perpendicular to 3y + 1 = x and PQ crosses the x-axis at (2, 0), find its equation. Therefore gradient of PQ = - 3 y = - 3x + 6 Equation of line : y – y 1 = m (x – x 1 ) y – 0 = - 3 (x – 2) P Q Rearrange: 3y + 1 = x
27. 28. Example 2 Find the equation of the straight line passing through A(4,5) and perpendicular to the line x + 2y – 4 = 0. Rearrange: x + 2y - 4 = 0 Therefore gradient of required line = 2 y = 2x - 3 Equation of line : y – y 1 = m (x – x 1 ) y – 5 = 2 (x – 4) A(4,5 )
28. 29. b) These 2 lines intersect at F . Find the coordinates of F. Sub (1) into (2) Sub into (1) y = 2(2) – 3 = 1 Therefore, F = (2,1). y = 2x – 3… ……..(1) x + 2y – 4 = 0 …..(2) x + 2(2x - 3) – 4 = 0 5x – 10 = 0 x = 2
29. 30. Perpendicular Bisector If PQ is the perpendicular bisector of MN, then MZ = ZN (Same distance) M N P Z Q
30. 31. Q1) 2 points A and B have coordinates (-1, -2) and (7, 4) respectively. Given that the perpendicular bisector of the line joining A and B meets the y-axis at C, calculate the coordinates of C. TRY THESE QUESTIONS NOW… Q2) Find the equation of the perpendicular bisector of the line joining A (-7, 2) and B(-1, 10). This perpendicular bisector meets the x-axis at C. Calculate the length of CM, where M is the midpoint of AB.
31. 32. Intersection All non-// straight lines will intersect at 1 point. However, a straight line and a curve may intersect at more than 1 point. A A B A
32. 33. Solving for intersection points To find coordinates of intersection point/s, ALWAYS solve the equations simultaneously .
33. 34. Can use ELIMINATION/ SUBSTITUTION method Can only use SUBSTITUTION method B A A
34. 35. Area Of A Polygon If we are given ALL the coordinates of the vertices of a polygon we can find the area easily with the use of a formula.
35. 36. Area Of A Polygon Area of a n-sided polygon = where (x 1 ,y 1 ), (x 2 ,y 2 )… are thecoordinates of its vertices.
36. 37. Area Example Find the area of the figure shown below.
37. 38. ‘ Shoelace’ Method
38. 39. Area Is there a need to apply the formula to find the area of this triangle?
39. 40. <ul><li>Q1) The lines x – y – 2 = 0 and 2x – 5y – 7 = 0 intersect at the point P. </li></ul><ul><li>Find the coordinates of P. </li></ul><ul><li>The line through P with gradient 2 meets the y-axis at A. Calculate the area of triangle APB if B is (5,12). </li></ul>TRY THESE QUESTIONS NOW… Q2) Calculate the distance of the point A(5, 8) from M, the mid-point of the line joining the points B(-1, 10) and C(3, 2). Show that AM is perpendicular to BC. Calculate the area of triangle ABC.
40. 41. <ul><li>Q3) The lines y = ax + 7 is parallel to the line y = 2x - 3. The line y = bx + 7 is perpendicular to the line y = 2x - 3. </li></ul><ul><li>State the value of a and b. </li></ul><ul><li>Calculate the perpendicular distance between the pair of parallel lines. </li></ul>AND TRY THESE TOO … Q4) 3 points have coordinates A(1, 2), B(9, 6) and C(3, 8). Find the equation of the perpendicular bisector of AB and show that it passes through C. Hence, or otherwise, find the area of triangle ABC.