1. ## Integral

Hello!
$
\int{\frac{dx}{x\sqrt{x^2-2x-1}}}
$

Using the Euler substitutions $\sqrt{x^2-2x-1} = t-x$, I come up with the result $2\arctan{(\sqrt{x^2-2x-1}+x)}.$Is the result right? I'm kinda suspicious!

Thanks