# Math Help - Finding the derivative...

1. ## Finding the derivative...

I need help with finding a derivative.

$x(x-8)^2$

How would this work?

2. ## Re: Finding the derivative...

Originally Posted by alane1994
I need help with finding a derivative.

$x(x-8)^2$
Product rule: $[f^{\prime}]g+f[g^{\prime}]$.

$[1](x-8)^2+x[2(x-8)]$

3. ## Re: Finding the derivative...

All I can say now is... duh!

4. ## Re: Finding the derivative...

Or you could just multiply out the expression.

$x(x-8)^2 = x(x^2-16x+64)$
$=x^3-16x^2+64x$