How can i express the $\displaystyle \int\frac{(x^2-1)}{(x^2+1)\sqrt{x^4-1}}dx$
Try: $x=\tan t, dx=\sec^2(t)dt$
$\displaystyle \int\frac{(\tan^2t-1)}{\sqrt{\tan^4t-1}}dt=\int\sqrt{\sin^2t-\cos^2t}dt =\int\sqrt{1-2\cos^2t}dt$
Could some help me how i express in elliptical form, Thanks