How to evaluate this expression: $∫\frac{\sin2x}{(1 - \cos2x)^4}\:\mathrm{d}x$? 
How to evaluate: $$∫\frac{\sin2x}{(1 - \cos2x)^4}\:\mathrm{d}x$$ If anyone knows the answer, please help.


$$
\int \frac{\sin 2x dx}{(1 - \cos 2x)^4} = \frac{1}{2}\int\frac{\sin 2x d(2x)}{(1 - \cos 2x)^4} = \frac{1}{2}\int \frac{d(1 - \cos 2x)}{(1 - \cos 2x)^4} = \frac{1}{2}\int u^{-4}du
$$
$$
= -\frac{1}{6}(\cos 2x)^{-3} = -\frac{1}{6\cos^3(2x)} + C
$$
