Inverse Functions
1. Consider the function (
f : x maps to - 2) with domain
A = {1, 3, 4, 7}. Then the range of the function is
B = {-1, 1, 2, 5}. The arrow diagram representing this function is shown as below.

2. If the arrows of (a) are reversed, the arrow diagram in (b) is obtained. A new function having domain B and range A is formed from the function
f. This new function is called the inverse function of f and is denoted by
f-1 .
3. To Find the inverse function,
f−1(x)
of
f(x)
•
Put the function equal to
y.
•
Rearrange to give x in term of
y.
•
Rewrite as
f−1(x)
replacing y by x.
Example: Given
f(x)=5x−4
, find the inverse function.