Question

Compute the derivative of f(x)=sin²​x

Answer 1

$$\begin{gathered} y={\sin }^{2}x \\ Let\sin x=t \\ y=t^2 \\ \frac{dy}{dx}=\frac{d{t}^2}{dx}=\frac{d{t}^2}{dt}\times \frac{dt}{dx}=2t\frac{dt}{dx}=2\sin x\frac{d\sin x}{dx}=2\sin x\cos x \end{gathered}$$