AlgebraLab

Algebra II Recipe: Inverse of a Function

By G Redden

A. Finding the Inverse of a Function
  1. Switch the x and y variables only.
  2. Solve the equation for y. (f-1 indicates the inverse)
  3. Graph the equation to determine if the inverse is a function.
1.
Find the inverse of y = 2x - 4
2.
Find the inverse of f(x) = (1/2)x3 - 2
B. Verifying Two Functions are Inverses
  • Given f(x) and g(x), if f[g(x)] = x and g[f(x)] = x, then the functions are inverses.
3.
Verify that f(x) = 2x + 1 and g(x) = (1/2)x - (1/2) are inverses.