第1991题：indefinite integrals

Solve $\int \sin^2(2x)dx$ .

A. $x-\dfrac{\sin 4x}{4}$ $+C$

B. $\dfrac{x}{2} -\dfrac{\sin 4x}{8}$ $+C$

C. $\dfrac{x}{4} -\dfrac{\cos 4x}{4}$ $+C$

D. $\dfrac{x}{4} -\dfrac{\cos 4x}{8}$ $+C$

tip: We need to use the following identity:

$\sin^2(x) =\dfrac{1-\cos(2x)}{2}$