2. Graphs of common functions
It is important to be able to sketch
these from memory.
3. PARENT FUNCTIONS
A parent function is the simplest
function that still satisfies the
definition of a certain type of function.
For example, linear functions which
make up a family of functions, the
parent function would be y = x.
11. The transformations are
(1) Vertical
(2) Horizonal
(3) Stretch/Compression.
(4) Reflection in the x-axis
(whenever the sign in front is
negative)
12. VALUE of a
For f(x) = x (Linear functions)
It general form is given by: f(x)=ax+d
if |a|>1, vertical stretch (narrow)
makes the graph move closer to y-axis
if |a|<1, vertical shrink (opens wide)
makes the graph move way from y-
axis
13. SIGN of a
for negative in front of a, flip over
(i.e..Reflection in x-axis)
14. Positive k means, move k-units up
Negative k, move k-units down
k represents vertical shift
15. Vertical Translation
The graph of y = f(x)
+ d is the graph of y =
f(x) shifted up d
units;
The graph of y = f(x)
d is the graph of y =
f(x) shifted down d
units.
2
( )
f x x
2
( ) 3
f x x
2
( ) 2
f x x
16. In general, a vertical translation
means that every point (x, y) on the
graph of f(x) is transformed to (x, y
+ c) or (x, y – c) on the graphs
of
or respectively.
17. Horizontal Translation
The graph of y = f(x
c) is the graph of y
= f(x) shifted right c
units;
The graph of y = f(x
+ c) is the graph of y
= f(x) shifted left c
units.
2
( )
f x x
2
2
y x
2
2
y x
18. The values that translate the graph of a
function will occur as a number added
or subtracted either inside or outside a
function.
Numbers added or subtracted inside
translate left or right, while numbers
added or subtracted outside translate
up or down.
( )
y f x c d
19. Sketch the following:
( ) 3
f x x
2
( ) 5
f x x
3
( ) ( 2)
f x x
( ) 3
f x x
20. Combining a vertical & horizontal shift
Example of
function that is
shifted down 4
units and right 6
units from the
original function.
( ) 6
)
4
( ,
g x x
f x x
21. To remember the difference between
vertical and horizontal translations,
think:
“Add to y, go high.”
“Add to x, go left.”
Helpful Hint
22. Use the basic graph to sketch the
following: TRY
( )
f x x
( )
f x x
2
( )
f x x
( )
f x x
23. Example
Write the equation of the graph obtained
when the parent graph is translated 4 units
left and 7 units down.
Parent graph:
Transformation:
3
y x
3
( 4) 7
y x
24. Example
Explain the difference in the graphs
2
( 3)
y x
2
3
y x
Horizontal Shift Left 3 Units
Vertical Shift Up 3 Units
25. Describe the differences between the
graphs
Try graphing them…
2
y x
2
4
y x
2
1
4
y x
26. A combination
If the parent function is
Describe the graph of
2
y x
2
( 3) 6
y x
The parent would
be horizontally
shifted right 3
units and
vertically shifted
up 6 units
27. If the parent function is
What do we know about
3
y x
3
2 5
y x
The graph would be
vertically shifted down 5
units and vertically
stretched two times as
much.
28. What can we tell about this
graph?
3
(2 )
y x
It would be a cubic function reflected
across the x-axis and horizontally
compressed by a factor of ½.
29. If a is positive, then the
graph will go up.
If a is negative, then the
graph will go down.
30. Transformations of graphs
y = a(x - h)²+k
h is the horizontal shift. The
graph will move in the opposite
direction.
K is the vertical shift. The
graph will move in the same
direction.
If a is positive, then the graph
will go up.
31. For example: y = x² + 6
y = (x – 0)² + 6, so the V.S. is up 6 and the H.S. is
none. Therefore, the vertex is
V (0, 6).
Since a is positive, the direction of the parabola is
up.
Since a is 1, then the parabola is neither fat or
skinny. It is a standard parabola.