Which change of variable would most directly simplify evaluating the integral ?

MATHEMATICS · Single correct · A Level · Mathematics · Integration · Integration

Problem

Which change of variable would most directly simplify evaluating the integral

\displaystyle\int 6x\,(3x^{2}+4)^{4}\,dx

? (a)

u = 6x

(b)

u = (3x^{2}+4)^{4}

(c)

u = 3x^{2}+4

(d)

u = x^{2}+4