Question

Find the derivative of r(θ) = θ^2(sinθ) + 2θcosθ

Answer 1

use the chain rule+product rule
i will write x instead of theta
r'(x)=2xsinx+x^2cosx+xcosx-2xsinx

Answer 2

using the fact that h(x)=g(x)j(x)
h'(x)=g'(x)j(x)+g(x)j'(x)

Answer 3

How did you get xcosx? Isn't d/dx 2x=2?