nilai dari integral tertentu π/4|0 (2sin3xcosx)dx adalah

integral 2 sin3x cos x dx dengan batas atas π/4 dan batas bawah 0
= integral 2 sin3x cos x dx
= integral sin (3+1) + sin (3-1)
= integral sin4x + sin2x dx
= -1/4cos4x -1/2cos2x + c

x = π/4 
= -1/4(cos180) -1/2(cos90)
= -1/4(-1) -1/2(1)
= 1/4 - 1/2
= 1/4 - 2/4
= -1/4

x = 0
= -1/4(cos0) -1/2(cos0)
= -1/4 -1/2
= -1/4 - 2/4
= -3/4

⇒ -1/4 - (-3/4) = 2/4 = 1/2