What Is Inverse Function?
An inverse function undoes what the original function does: if a function f takes x to y, its inverse f⁻¹ takes y back to x. A function only has an inverse if it's one-to-one, meaning no two different inputs produce the same output. Graphically, a function and its inverse are mirror images across the line y = x.
Example
If f(x) = 2x + 3, its inverse is f⁻¹(x) = (x − 3)/2. Check: f(5) = 2(5)+3 = 13, and f⁻¹(13) = (13−3)/2 = 5, back where you started.