Question

What is the derivative of `(cos x)^2 - cos x`?

Answer 1

`sinx-sin2x.`

Explanation:

`d/dx[ cos^2x-cosx]=d/dx((cosx)^2)-d/dxcosx =2*(cosx)*d/dxcosx-(-sinx)=2cosx(-sinx)+sinx=sinx-2cosxsinx=sinx-sin2x.`