# G.4.9.1 Part 1 What's an Inverse Function?

- Author:
- Katie Akesson

All functions have inputs and outputs.
An

**inverse function**switches which variable is acting as the input and reverses the actions of the original function. In the example below:- the function,
*f*, takes in 4 and outputs 8 - the inverse funtion,
*f*^{-1}, takes in 8 and outputs 4

What is the action of the original function, *f*, above?

What is the reverse action performed by the inverse funtion, *f *^{-1}, above?

What is the action of the original function, *g*, above?
What is the reverse action performed by the inverse funtion, *g *^{-1}, above?

In general, what does the sine function take in and what does it output? In general, what's going on with the inverse sine function?

Based on we just learned, what do you think inverse trig functions are used for?