# general power rule

• May 28th 2011, 05:06 PM
purplec16
general power rule
Using the general power rule to find the derivative of the function

$f(x)= {({x}^{2 }-9 })^{\frac{2}{3 } }$

in this case do they mean the chain rule...if not then i'm not sure how to expand the function
• May 28th 2011, 05:13 PM
Deveno
in order to use the chain rule, you will have to invoke the power rule as well. you have: (something)^(a power).
• May 28th 2011, 05:23 PM
Quacky
Quote:

Originally Posted by purplec16
Using the general power rule to find the derivative of the function

$f(x)= {({x}^{2 }-9 })^{\frac{2}{3 } }$

in this case do they mean the chain rule...if not then i'm not sure how to expand the function

The general power rule states that for any function of the form $[g(x)]^n$, the derivative will be:
$n[g'(x)][g(x)^{n-1}]$