If a function f is one-to-one with domain A and range B, then there is a one-to-one function f –1, the inverse of f, with domain B and range A.

To find an inverse function:

Step 1: Switch x and y.

Step 2: Solve for y.

Step 3: Replace y with f –1(x).

Khan Academy Practice:

• Intro to Inverse Functions

• Inverse Functions 

• A quick, visual way to determine if a function will have an inverse that is also a function. 

• If a function passes this test, it is "one-to-one."

Two functions, f (x) and g(x), are inverse functions if f (g(x)) = x for every value of x in the domain of g, and g(f (x)) = x for every value of x in the domain of f. 

Khan Academy Practice:

• Verifying Inverse Functions with Composition