Find the derivative.

Question

anonymous · Answer

$$\frac{ 1 }{\left( x+1 \right)^{2}  } $$

anonymous · Answer

You may want to write the expression as (x+1)^-2 and now use the power rule.

anonymous · Answer

Oh okay thanks. I'll need chain rule too, right? Or is that not needed for this problem?

anonymous · Answer

Yes.

anonymous · Answer

But here, the derivative of (x + 1) is 1. so chain rule doesnt change anything.

anonymous · Answer

the answer that my textbook gives is $$\frac{ -2 }{\left( x+1 \right) ^{3} }$$.
how do I get to that answer?

anonymous · Answer

that's what I can't figure out

anonymous · Answer

exactly..thats what you get....using the pwer rule, you get

-2(x + 1) ^ (-3) which is identical to your book's answer.

anonymous · Answer

Keep in mind, that (x+1) ^ (-3) = 1/(x+1)^3

anonymous · Answer

Oh. I see what I was doing wrong. When I used the power rule, I subtracted the exponent wrong so I wasn't getting a -3. Thank you :)