Hi,
How to i find the integral:
dx/((x+1)*(1+x^2)^(0.5))
If the problem is
$\displaystyle \int \frac{dx}{(x+1)\sqrt{1+x^2}}$
Make two substitutions, first $\displaystyle x = \tan \theta$ this will give
$\displaystyle \int \frac{d \theta}{ \sin \theta + \cos \theta}$
Next, let $\displaystyle \theta = 2 \tan^{-1} z$, this gives
$\displaystyle -2 \int \frac{dz}{z^2-2z-1}$
Which you should be able to do. Of course you could combine the substitutions.