2 x -------- 2 (x + 1)
x^2/(x + 1)^2
1 + (1 + x)^(-2) - 2/(1 + x)
1 2 1 + -------- - ----- 2 1 + x (1 + x)
x^2/(1.0 + x)^2
1 + 2*x 1 - ------------ 2 1 + x + 2*x
1 - (1 + 2*x)/(1 + x^2 + 2*x)