calculus - A tricky integral - $int_0^1 sqrt{frac{1}{(1-t^2)^2}-frac{(n+1)^2t^{2n}}{(1-t^{2n+2})^2}}dt $

$$

\mathbf{\mbox{Evaluate:}}\qquad
\int_{0}^{1} \sqrt{\frac{1}{\left(1 - t^{2}\right)^2} -
\frac{\left(n + 1\right)^{2}\,t^{2n}}{\left(\, 1 - t^{2n+2}\,\,\right)^{2}}}
\,\,\mathrm{d}t
$$
where $n$ is any positive integer.

Introduction: This integral came up while studying the distribution of the roots of random polynomials - and I can't crack it. It seems impervious to methods of integration I know. Neither Mathematica nor Wolfram-Alpha could find a closed form, not only for this general integral, but any special case of $n>1$.

My attempt:

For $n=1$, the integral is pretty trivial to compute - expanding the integrand gives:
$$\int_0^1 \sqrt{\frac{1}{t^4-2 t^2+1}-\frac{4 t^2}{t^8-2 t^4+1}}$$
Which simplifies quite easily to:
$$\int_0^1 \frac{1}{t^2+1}$$
The antiderivative of the integrand is $\tan^{-1}{t}$. Evaluating at the limits gives:
$$\int_0^1 \sqrt{\frac{1}{t^4-2 t^2+1}-\frac{4 t^2}{t^8-2 t^4+1}}=\frac{\pi}{4}-0=\frac{\pi}{4}$$
However, this method does not work for $n>1$, and niether does any method I know of.

Numerical values:
Listed below are the approximate numerical values for this integral. Neither Wolfram Alpha nor the Inverse Symbolic calculator were able to find closed forms for these numbers.

$$n=2 \qquad 1.01868$$
$$n=3 \qquad 1.17241$$
$$n=4 \qquad 1.28844$$
$$n=5 \qquad 1.38198$$

$$n=6 \qquad 1.46049$$

Any help on this integral would be greatly appreciated. Thank you!

Answer

It appears that the integral when $n=2$ can be represented in terms of elliptic integrals:

$$
I(2)=\frac{\pi}{2}-\frac{1}{\sqrt{6}}\left(\Pi\left(\frac23\mid\frac13\right)-K\left(\frac13\right)\right).
$$

Here the arguments of elliptic functions follow Mathematica conventions: that is,

$$
K(m)=\int^{\pi/2}_{0}\frac{d\theta}{\sqrt{1-m\sin^2\theta}}
$$
and
$$
\Pi(n\mid m)=\int^{\pi/2}_{0}\frac{d\theta}{(1-n\sin^2\theta)\sqrt{1-m\sin^2\theta}}.
$$