Question

Evaluate ∫3x2sin(x3)cos(x3)dx by

(a) using the substitution u=sin(x3) and

(b) using the substitution u=cos(x3).

Explain why the answers from (a) and (b) are seemingly very different

Answer 1

Evaluate ∫3x2sin(x3)cos(x3)dx

Explanation:

hello (a) using the substitution u=sin(x3) because

du =3x²(cos x3)dx

you have ∫3x2sin(x3)cos(x3)dx = ∫udu=u²/2 +c............continu