1 ------------- 3 2 x + 2*x + x
1/(x^3 + 2*x^2 + x)
1/x - 1/(1 + x) - 1/(1 + x)^2
1 1 1 - - ----- - -------- x 1 + x 2 (1 + x)
1 ---------------- / 2 \ x*\1 + x + 2*x/
1/(x*(1 + x^2 + 2*x))
1/(x + x^3 + 2.0*x^2)
1 ------------- 3 2 x + x + 2*x
1/(x + x^3 + 2*x^2)
1 ---------- 2 x*(1 + x)
1/(x*(1 + x)^2)
1 ----------------- x*(1 + x*(2 + x))
1/(x*(1 + x*(2 + x)))