2 x --------- 4 / 2 \ \x + 1/
x^2/(x^2 + 1)^4
(1 + x^2)^(-3) - 1/(1 + x^2)^4
1 1 --------- - --------- 3 4 / 2\ / 2\ \1 + x / \1 + x /
x^2/(1.0 + x^2)^4
2 x --------------------------- 8 2 6 4 1 + x + 4*x + 4*x + 6*x
x^2/(1 + x^8 + 4*x^2 + 4*x^6 + 6*x^4)