Hey, I cannot figure out how to solve this integral. My teacher says we can't use the table of integrals in the back of the book, and have to solve it ourselves. Here it is:

$\displaystyle \int{\arctan{x}}dx$

And the answer is supposed to be:

$\displaystyle \int{\arctan{x}}dx=x*\arctan{x}-\ln{\sqrt{1+x^2}}+C$

Please help!!!

Thanks