I'm not sure how to approach this...

My problem is I don't i don't know what to substitute in for f(x) and g(x) when i try to use integration by parts for this particular integral.

$\displaystyle \int ln(2x+1) dx$

I can kind of get thorough it about halfway if i use $\displaystyle f(x)=ln(2x+1)$ and $\displaystyle g(x)=dx$. but i end up with my second integral being this:

$\displaystyle \int \frac{2x}{2x+1}dx$

and i'm not sure how to get

$\displaystyle \frac{1}{2}(2x+1)ln(2x+1)-x+C$

As my answer if i integrate that last one. I would post all my work but i'm kind of in a hurry. So thank you and I appreciate your help. :)