1.5 Inverse Function

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 ) = 5 x 4   , find the inverse function.



 


   

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