2. FunctionsFunctions
Imagine functions are like the dye you useImagine functions are like the dye you use
to color eggs. The white egg (x) is put into color eggs. The white egg (x) is put in
the function blue dye B(x) and the result isthe function blue dye B(x) and the result is
a blue egg (y).a blue egg (y).

3. The Inverse Function “undoes” what the functionThe Inverse Function “undoes” what the function
does.does.
The Inverse Function of the BLUE dye is bleach.The Inverse Function of the BLUE dye is bleach.
The Bleach will “undye” the blue egg and make itThe Bleach will “undye” the blue egg and make it
white.white.

4. In the same way, the inverse of a givenIn the same way, the inverse of a given
function will “undo” what the originalfunction will “undo” what the original
function did.function did.
For example, let’s take a look at the squareFor example, let’s take a look at the square
function: f(x) = xfunction: f(x) = x22
33
xx f(x)f(x)
3333333333 99999999999999
yy ff--1--1
(x)(x)
99999999999999 33333333333333
x2 x

5. 555555555555 25252525
2525
2525
25252525
2525
25252525252555 5555555555555555
In the same way, the inverse of a givenIn the same way, the inverse of a given
function will “undo” what the originalfunction will “undo” what the original
function did.function did.
For example, let’s take a look at the squareFor example, let’s take a look at the square
function: f(x) = xfunction: f(x) = x22
xx f(x)f(x) yy ff--1--1
(x)(x)
x2
x

6. 111111111111111111111111 121121121121121121121121121121121121121121121121121121121121121121121121121121121121 11111111111111111111111111111111
In the same way, the inverse of a givenIn the same way, the inverse of a given
function will “undo” what the originalfunction will “undo” what the original
function did.function did.
For example, let’s take a look at the squareFor example, let’s take a look at the square
function: f(x) = xfunction: f(x) = x22
xx f(x)f(x) yy ff--1--1
(x)(x)
x2 x

7. Graphically, the x and y values of aGraphically, the x and y values of a
point are switched.point are switched.
The point (4, 7)The point (4, 7)
has an inversehas an inverse
point of (7, 4)point of (7, 4)
ANDAND
The point (-5, 3)The point (-5, 3)
has an inversehas an inverse
point of (3, -5)point of (3, -5)

8. -10 -8 -6 -4 -2 2 4 6 8 10
-10
-8
-6
-4
-2
2
4
6
8
10
Graphically, the x and y values of a point are switched.Graphically, the x and y values of a point are switched.
If the function y = g(x)If the function y = g(x)
contains the pointscontains the points
then its inverse, y = gthen its inverse, y = g-1-1
(x),(x),
contains the pointscontains the points
xx 00 11 22 33 44
yy 11 22 44 88 1616
xx 11 22 44 88 1616
yy 00 11 22 33 44
Where is there aWhere is there a
line of reflection?line of reflection?

9. The graph of aThe graph of a
function andfunction and
its inverse areits inverse are
mirror imagesmirror images
about the lineabout the line
y = xy = xy = f(x)y = f(x)
y = fy = f-1-1
(x)(x)
y = xy = x

10. Find the inverse of a function :Find the inverse of a function :
Example 1:Example 1: y = 6x - 12y = 6x - 12
Step 1: Switch x and y:Step 1: Switch x and y: x = 6y - 12x = 6y - 12
Step 2: Solve for y:Step 2: Solve for y: x = 6y −12
x +12 = 6y
x +12
6
= y
1
6
x + 2 = y

11. Example 2:Example 2:
Given the function :Given the function : y = 3xy = 3x22
+ 2+ 2 find the inverse:find the inverse:
Step 1: Switch x and y:Step 1: Switch x and y: x = 3yx = 3y22
+ 2+ 2
Step 2: Solve for y:Step 2: Solve for y: x = 3y2
+ 2
x − 2 = 3y2
x − 2
3
= y2
x − 2
3
= y