2*n x --------- 2 / n \ \x - 1/
x^(2*n)/(x^n - 1)^2
1 + (-1 + x^n)^(-2) + 2/(-1 + x^n)
1 2 1 + ---------- + ------- 2 n / n\ -1 + x \-1 + x /
n -1 + 2*x 1 + --------------- 2*n n 1 + x - 2*x
1 + (-1 + 2*x^n)/(1 + x^(2*n) - 2*x^n)
n / 2\ \x / ---------- 2 / n\ \-1 + x /
(x^2)^n/(-1 + x^n)^2