Question

Derivative of cos(2x+3) w.r.t. x?

Answer 1

`-2 sin(2x+3)`

Explanation:

Given: `f(x) = cos(2x+3)`

Use `d/dx (cos x) = -sin x`

The chain rule: `(cos u)' = (-sin u) u' = -u' sin u`

Let `u = 2x + 3; " " u' = 2`

`f'(x) = -2 sin(2x+3)`