http://euler.vaniercollege.qc.ca/web...8ca5108931.png

my $\displaystyle u = (x^2+1)$, $\displaystyle du = 2x$

$\displaystyle 4 \int (2x+1)/(x^2+1)$

I would like to turn that into du/u but there's a + 1 in the numerator, which isn't part of du's value. What am I supposed to do?