integral sin 4x cos 2x dx ? tentukan hasil trigonometrinya ?!

sin 4x = 2sin 2x cos 2x

dcos 2x = -2sin 2x dx
sin 2x dx = (-1/2)dcos 2x

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