# Find (f^-1) (a) if f(x)

## Homework Statement

Find (f^-1) (a) if f(x) = sqrt of (x^3+x^2+x+2) and a = 4?

## Homework Equations

Find (f ^-1) (a) = 1/ f ^1( f ^-1(a))

## The Attempt at a Solution

Take Derivative
1/2(x^3+x^2+x+2)^-(1/2)
do I need to do chain rule?
I am lost
this problem can help me pass the class
plz help

$$x = f^{-1}(a) \iff a = f(x)$$
So basically, what you need to do is solve the equation $$4 = \sqrt{x^3 + x^2 + x + 2}$$