Integration by Substitution https://www.youtube.com/watch?v=pgn-wCewSoA Integration by Substitution (1) When integrand is a function i.e.,∫f[?(x)] ?'(x) dx: Here, we put ?(x)=t, so that ?'(x) dx=dt and in that case the integrand is reduced to ∫f(t) dt.(2) When integrand is the product of two factors such that one is the derivative of the others i.e., I = ∫f(x)f'(x) … [Read more...] about Integration by Substitution