Question

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

Answer 1

We have a function,

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

and we are asked to find its inverse function.

An inverse function essentially gets you the original value that was dropped into a function.

For example,

If I put 5 into $f(x)$ I will get 24. Now If I take 24 and put it into the inverse function I have to get number 5 back.

The way to determine the inverse function swap the x and the $f(x)$, then solve for $f(x)$,

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

$f(x)^2=x+1$

$f(x)=\pm\sqrt{x+1}$

Of course the notation demands that the obtained function be called,

$f^{-1}(x)=\pm\sqrt{x+1}$

Hope this helps :)