## Key Concepts

• The inverse of a quadratic function is a square root function.
• If ${f}^{-1}$ is the inverse of a function f, then f is the inverse of the function ${f}^{-1}$.
• While it is not possible to find an inverse of most polynomial functions, some basic polynomials are invertible.
• To find the inverse of certain functions, we must restrict the function to a domain on which it will be one-to-one.
• When finding the inverse of a radical function, we need a restriction on the domain of the answer.
• Inverse and radical and functions can be used to solve application problems.

## Glossary

invertible function
any function that has an inverse function