- A function f(x) is one-to-one if it does not assign the same value to two different elements of its domain.

- If f(x) is a 1-1 function, then it has an inverse function f

^{-1}defined by f

^{-1}(y)=x if f(x)=y, for all y in the range of f.

- The domain of f

^{-1}is the range of f, and the range of f

^{-1}is the domain of f.

- To find a formula for f

^{-1}, we can set y = f(x), solve for x in terms of y, and set f

^{-1}(y) = x.