I wish to integrate
$$\int \frac{1+x^2}{(1-x^2)\sqrt{1+x^4}}\ dx.$$
I have tried substituting $x = \sqrt{\mathrm{tan}\ u}$ but then I get a root at the bottom which I can't get rid of. Also I have tried $x = \tan u$ but that isn't any better.
I wish to integrate
$$\int \frac{1+x^2}{(1-x^2)\sqrt{1+x^4}}\ dx.$$
I have tried substituting $x = \sqrt{\mathrm{tan}\ u}$ but then I get a root at the bottom which I can't get rid of. Also I have tried $x = \tan u$ but that isn't any better.