Question

Вычислите определённый интеграл

Answer 1

$\huge \\ \int_{0}^{\pi\over4}\cos{4x}\mathrm{dx}=\begin{vmatrix} 4x=t,\mathrm{dx}={\mathrm{dt}\over4},t_1=0, t_2=\pi \end{vmatrix}={1\over4}\int_{0}^{\pi}\cos{t}\mathrm{dt}={1\over4}\sin{t}|_{0}^{\pi}={1\over4}(\sin{\pi}-\sin{0})=0$