Question

Tolong dijawab dengan cara

Answer 1

(0 -->π/3) ∫ sin x cos x cos 3x dx
(0--> π/3) ∫ 1/2 (2 sin x cos x). cos 3x dx
(0--> π/3) ∫ 1/2 cos 3x sin 2x dx
(0-->π/3) ∫ 1/2 { 1/2 (2 cos 3x  sin 2x) dx
(0--> π/3) ∫ 1/4 (sin 5x - sin x) dx
=  [ -1/20 cos 5x + 1/4 cos x)|(π/3 ...0)
= -1/20 ( cos π/3 - cos 0) + 1/4 (cos π/3 - cos 0)
= -1/20 (1/2 -1) + 1/4(1/2 - 1)
= - 1/20 (-1/2) + 1/4(-1/2)
= 1/40 - 1/8
= 1/40 - 5/40
= -4/40
= - 1/10