\documentclass[a4paper,12pt]{article}
\newcommand\ds{\displaystyle}
\begin{document}

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QUESTION

Find $\ds\int\sin^2(2x)\,dx$.

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ANSWER

$\ds\int\sin^2(2x)\,dx
=\int\left\{\frac{1-\cos(4x)}{2}\right\}\,dx
=\frac{x}{2}-\frac{\sin(4x)}{8}+c$




\end{document}