2.) ∫ (2.cos3x.sin7x) dx

int (2 cos(3x) sin(7x)) dx
= int (sin(4x) + sin(10x)) dx
u = 4x → du = 4 dx → dx = (1/4) du
v = 10x → du = 10 dx → dx = (1/10) du
= (1/4) int sin(u) du + (1/10) int sin(v) dv
= (1/4)(-cos(u)) + (1/10)(-cos(v)) + c
= -(1/4) cos(4x) - (1/10) cos(10x) + c
ato dlm bntuksusunan lain....