Monday, October 11, 2010

VERTICAL AND HORIZONTALTRANSFORMATION OF A FUNCTION.

Last Friday, We learned about the vertical and horizontal translations of a given function.

REVIEW: VERTICAL TRANSLATION
y=f(x)+k
y=f(x)-k
Where K is responsible for the vertical movement of the whole function.

EXAMPLE :
A. f(x)=x2

B. f(x)+2
SOLUTION:From parent function.The whole graph will move 2 points up.
You can also use table of values.

X

Y

-2




-1


0


1


2

( -2)2 + 2

4+2

=6


( -1)2 + 2

1+2

=3


( 0)2 + 2

0+2

=2


(1)2 + 2

1+2

=3

(2)2 + 2

4+2

=6


C. f(x)-4
SOLUTION:From parent function.The whole graph will move 4 points down.
You can also use table of values.

X

Y

-2



-1



0


1


2

( -2)2 -4

4-4

=0


( -1)2 -4

1-4

=-3



( 0)2 -4

0-4

=-4


(1)2 -4

1-4

=-3

(2)2 +-4

4-4

=0


NOTE: Given the equation of y=f(x)+ k , The x value does not change(x, y+ k ).


REVIEW: HORIZONTAL TRANSLATION
y=f(x-h)
y=f(x+h)
Where H is responsible for the horizontal movement of the whole function.
ALWAYS remember to read the H value as OPPOSITE.

EXAMPLE :
A. f(x)=x2
B. f(x-4)
SOLUTION:From parent function.The whole graph will move 4 points to the right.
You can also use table of values.

X

Y

3


4

5

( 3-4)2

-1^2

=1

( 4-4)2 02

=0

( 5-4)2

12

=1

C. f(x+3)
SOLUTION:From parent function.The whole graph will move 3 points to the left.

X

Y

-4

-3

-2

( -4+3)2

-12

=1

( -3=3)2

02

=0

( -2+3)2

12

=1

NOTE: Given the equation of y=f(x+ h) , The y value does not change(x+ h,y)

QUICK EXAMPLE
:COMBINATION OF VERTICAL AND HORIZONTAL TRANSLATION
graph y=(x+3)2 +4

SOLUTION:
Starting from parent function y=x2 , The whole graph will move 3 points to the left because of (x+3)2[remember we read h as opposite].From (x+3)2 , the graph will move four points down because of the k value +4 from the equation (x+3)2 + 4.

1 comment:

  1. For your "Quick Example" question, did you mean to use the question: y=(x+3)^2 -4 rather than y=(x+3)^2 +4? If it was +4 you would move 4 points up instead of down. For some reason you have the right equation in red font on the chart, just not in the description.

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