- #1

aero13

- 2

- 0

## Homework Statement

Find (f−1)'(a).

f(x) = 5x^3 + 3x^2 + 5^x + 4, a = 4

## Homework Equations

I'm not entirely sure but I assume I have to use d/dx(f-1) = 1/f '(f-1(x))

## The Attempt at a Solution

So far I switched y and x. Found dx/dy to be 15y^2 + 6y + 5. Then I switched dx/dy to dy/dx so the answer became 1/15^2 + 6y +5 and I plugged in 4 to get 1/269. But the answer is wrong