Question

$\int\limitssin2xsin8x \, dx$

Answer 1

∫2xsin8x=2∫xsin8x
интегрируем по частям    ∫fdg=fg-∫gdf   f=x     dg=sin8xdx     df=dx   g=-cos8x/8
-1/4*xcos8x/8+1/4∫cos8x=1/32*sin8x-1/4*xcos8x/8+C