5 x ----------- 4 2 x + x + 1
x^5/(1.0 + x^2 + x^4)
5 x --------------- 2 / 2\ 1 + x *\1 + x /
5 x ------------------------- / 2\ / 2 \ \1 + x + x /*\1 + x - x/
3 x + x x - ----------- 2 4 1 + x + x