Question

differentiate -4x^2cosx

Answer 1

Okay first I say apply the constant rule
(cF)'=c(F)'=cF'

Answer 2

so basically I'm saying let's look at x^2cos(x)
and find the derivative of that
then just come back and multiply it by -4

Answer 3

x^2cos(x) is a product though
so we use the product rule
do you know the product rule?