itegral 2sin4x cos 2x dx

InTegraL

sin 4x = 2 sin 2x cos 2x
2 sin 4x cos 2x = 4 cos² 2x sin 2x

∫2 sin 4x cos 2x dx
= 4 ∫cos² 2x sin 2x dx
= 4 ∫cos² 2x . (-1/2) dcos 2x
= -2 ∫cos² 2x dcos 2x
= -2/3 cos³ 2x + C