Can some one explain why I am getting this wrong

1. Aug 2, 2008

viciousp

Can some one explain why I am getting this wrong[SOLVED]

1. The problem statement, all variables and given/known data
Evaluate
$$\int ln(x+x^{2}) dx$$

2. Relevant equations

3. The attempt at a solution
I integrated by parts to get down to $$xln(x+x^{2})-\int \frac{(2x-1)}{x+1}$$ I set $$u=1+x$$ which led to $$du=1 dx$$ and $$x=u-1$$ after so evaluation I got down to $$-(\int 2 du -\int \frac{1}{u} du)$$ and after more substitution and evaluation I got down to $$xln(x+x^{2})+ln\left|1+x \right|-2-2x +C$$, but my book says that I should have only got -2x and not that extra -2

Last edited: Aug 2, 2008
2. Aug 2, 2008

viciousp

Nevermind I figured it out

3. Aug 2, 2008

snipez90

Huh weird, this same problem was solved yesterday. Which book are you using for calculus if you don't mind me asking?

4. Aug 2, 2008

viciousp

Thomas Calculus, I still don't get how I messed up on substitution but I just long divided and got the answer

5. Aug 2, 2008

rock.freak667

You didn't need to use integration by parts though.