What is u3lnu(dudx) if u=3x?

1 Answer
Sep 26, 2017

Given: u3ln|u|(dudx);u=3x then dudx=3

Moving the multiplication by dudx in front of the logarithm:

(u33ln|u|)du=u44+(3u)(ln|u|1)+C

Reversing the substitution for u:

(u33ln|u|)du=(x3)44+(3(x3))(ln331)+C