How do you find the first derivative of x^3(x+2)(x-4)?
f(x ) = x^3(x+2)(x-4)
We could use the product/power rules, but I find just expanding this and using the power rule by itself is easier.
So we have
f(x) = x^3(x^2 - 2x - 8) = x^5 - 2x^4 - 8x^3
And
f ' (x) = 5x^4 - 8x^3 - 24x^2