Question

How do you find the derivative of `(sin2x)`?

Answer 1

We should use the chain rule:
`f(g(x)) = f'(g(x))*g'(x)`.
In our situation `f(x) = sin(x)` and `g(x) = 2x`. Then `f'(x) = cos(x)` and `g'(x) = 2`.

So `f(g(x)) = sin(2x) = f'(g(x))*g'(x) = cos(2x)*2 = 2cos(2x)`