Integral persial o∫π x cos 2x dx

∫ x cos 2x dx [π...0]
= ∫ x . 1/2 dsin 2x
= 1/2 ∫x dsin 2x
= 1/2 (x sin 2x - ∫ sin 2x dx)
= 1/2 (x sin 2x + 1/2 ∫ dcos 2x)
= 1/2 x sin 2x + 1/4 cos 2x [π...0]
= (0 + 1/4) - (0 + 1/4)
= 0