# Help with Integration by Parts Problem

• September 24th 2009, 07:50 AM
PD1337
Help with Integration by Parts Problem
While attempting to integrate ln(x+1)

I got it down to xln(x+1) - the integral of x/(x+1)

If integration by parts is done again the problem repeats itself.
My teacher tells me the answer is xln(x+1) - x + ln(x+1) + c

How did he get there?
• September 24th 2009, 08:00 AM
red_dog
$\int\frac{x}{x+1}dx=\int\frac{x+1-1}{x+1}dx=\int\left(1-\frac{1}{x+1}\right)dx$

Continue now.
• September 24th 2009, 08:02 AM
PD1337
Got it! Thanks for your help