# Math Help - integral problem

1. ## integral problem

Thanks!

2. Originally Posted by gralla55
Thanks!
Well, for the first one...
$\frac{x^2 + 1}{x^2 - 1} = 1 + \frac{2}{x^2 - 1}$

Does that give you any ideas?

-Dan

3. I allready solved that one, but I've got no idea on the 2nd.

4. Originally Posted by gralla55
I allready solved that one, but I've got no idea on the 2nd.
Well, the form of the integrand just screams "trig substitution" :
$tan( \theta ) = \frac{x^2 + 1}{x^2 - 1}$

The problem is that this attack is very messy. So messy that I decided to consult the "oracle" over on Mathematica's online integrator, which gave me a really messy answer. So messy that I am wondering if there isn't some typo in the problem?

-Dan

5. Actually, you're right. The fraction is supposed to be 2x/x^2-1 not x^2+1/x^2-1!