Hello Rajesh
We know that
∫ sin x = - cos x
If we have to integrate sin ax,
∫ sin ax = - cos x/a
The, number multiplied by x gets divided on integration.
Lets see the proof
Proof:
∫ sin ax dx
Let ax = t
so, a dx = dt
dx = dt/a
∫ sin ax dx = ∫ sin t (dt/a)
= 1/a ∫ sin t dt
= 1/a (- cos t) + C
Putting t = ax
= 1/a (- cos ax) + C
= - cos ax / a + C
Written on Nov. 11, 2017, 6:33 p.m.