Question

Differentiate cos $2x$

Answer 1

We have to find the derivative of cos$2x$

To differentiate cos$2x$, we use the chain rule.

Derivative of$f\left(g\right(x\left)\right)=f’\left(g\right(x)\times g’(x)$

$(d/dx)\cos 2x=-\sin 2x\times 2$

$=-2\sin 2x$

So the derivative of $\mathbf{cos}\mathbf{2}\mathit{x}$ is $\mathbf{-}\mathbf{2}\mathbf{}\mathit{s}\mathit{i}\mathit{n}\mathbf{}\mathbf{2}\mathit{x}$