Integration of Trigonometric Functions (1 Viewer)

[epsilon-]

Let B = ∫ from 0 to pi/4 of (cosθ sin^2 θ) dθ

I looked up the solution to this and it showed me two methods.

1. As integrand in the form of f'(x)sin^2 f(x), then B = [sin^3 θ] limits from 0 to pi/4

2. Using integration by substitution, let u = sinθ

I obviously went with method number 2. But method number 1 was amazing, I have never seen it in my life!!!

 

[Trebla]

They're both essentially the same thing just different notation

 

[D94]

You are really just skipping two or three extra steps of the substitution method (2) by using the reverse chain rule method (1).