# Differentiation - I thought I had finally got it, but im stuck again!

• Sep 12th 2012, 04:42 AM
cnotesjustfearless
Differentiation - I thought I had finally got it, but im stuck again!
Ok, the question is:

Differentiate: five over the square root of four + x
• Sep 12th 2012, 04:57 AM
a tutor
Re: Differentiation - I thought I had finally got it, but im stuck again!
$\frac{5}{\sqrt{4+x}}=5(4+x)^{-1/2}$

Use the chain rule.
• Sep 12th 2012, 05:02 AM
cnotesjustfearless
Re: Differentiation - I thought I had finally got it, but im stuck again!
thanks, i got that far. But its after that that I get lost.
The answer says -5 over 2 times the square root of 4 + x cubed

thankyou!