# Math Help - general power rule

1. ## 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

2. in order to use the chain rule, you will have to invoke the power rule as well. you have: (something)^(a power).

3. 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:
$n[g'(x)][g(x)^{n-1}]$