Question

If f(x) = x2 -1, what is the equation for f1(x)?

Answer 1

`f(x)=x^2-1`

1. First, replace f(x) with y

`y=x^2-1`

2. Replace every x with a y and replace every y with an x.

`x=y^2-1`

3. solve for y:

`\begin{gathered} y^2=x+1 \\ y=\pm\sqrt[]{x+1} \end{gathered}`

4. Replace y with f−1(x):

`f^(-1)(x)=\pm\sqrt[]{x+1}`