nilai integral dengan batas atas Π/4 dan batas bawah 0 (sin 3x cos3x) dx = ...

(0..π/4) ∫ (sin 3x cos 3x) dx


(0..π/4) ∫ 1/2 { 2 sin 3x cos 3x) dx

(0..π/4) ∫ 1/2 ( sin 6 x) dx

= 1/2. 1/6. [(- cos 6x) ](0...π/4)

= -1/12  [ cos 6x ] (0..π/4)
= - 1/12 [ cos 6(π/4) - cos 6(0)]
= - 1/12 [ 0 - 1]
= 1/12