A functionallows us to findfor any value ofWe just substitute the value forinto

Ifthen we findwhenby calculating

Inverting a function allows us to find x for any value ofif this is possible.

The Procedure is:

1. Write

2. Rearrange the equation to makethe subject.

3. Swapandover.

4. Replaceby

5. The graph ofmay be sketched by reflecting the graph ofin the line

Example: The graph ofis shown below.

Makethe subject:

Swapand

Replaceby