## anonymous 4 years ago f(x) = 1/(x^5-4 x). Then f' =

1. anonymous

f'= derivative of first times second minus derivative of second times first divided by the whole thing squared.

2. Xishem

$f(x)=\frac{1}{x^5-4x}$We need to use the quotient rule...$f'(x)=\frac{(x^5-4x)(0)-(1)(5x^4-4)}{(x^5-4x)^2}=\frac{5x^4-4}{(x^5-4x)^2}$

3. anonymous

what else do i need to do after that?

4. Xishem

That's it. That's the derivative of f(x).

5. Directrix

or f ' (x) =[ (4 - 5 x^4)] / [x^2 (x^4 -4) ^2]

6. Xishem

Directrix is right. I forgot to distribute through the -1. My answer was wrong.