# Could use help on a Chain Rule problem

• May 10th 2009, 08:14 PM
elong
Could use help on a Chain Rule problem
Hi. I was wondering if anybody on this forum can help me find the derivative of:

f(x) = [(√x^3 + 2) + 2x)^-2]

I'm pretty sure I'm messing up with the algebra somewhere. Any detailed steps would be appreciated. Thanks in advance.

Btw, this is how far I've gotten.

f'(x) = -2[(√x^3 + 2) + 2x)^-3 * (x^3 + 2)^1/2 + (2x)

Also, on another note. Is there a program I can download that allows me to type math symbols?
• May 10th 2009, 09:05 PM
TheEmptySet
Quote:

Originally Posted by elong
Hi. I was wondering if anybody on this forum can help me find the derivative of:

f(x) = [(√x^3 + 2) + 2x)^-2]

I'm pretty sure I'm messing up with the algebra somewhere. Any detailed steps would be appreciated. Thanks in advance.

Btw, this is how far I've gotten.

f'(x) = -2[(√x^3 + 2) + 2x)^-3 * (x^3 + 2)^1/2 + (2x)

Also, on another note. Is there a program I can download that allows me to type math symbols?

You don't need to download anything look in the FAQ for math symbols

$f(x)=[\sqrt{x^3+2}+2x]^{-2}$

Now when we take the derivative we get

$f'(x)=-2[\sqrt{x^3+2}+2x]^{-3}\left(\frac{1}{2}\frac{3x^2}{\sqrt{x^3+2}}+2 \right)$