2 c c ------ - - - 2 2 c c - 4
2 c -3 + ------- 2 -4 + c
-3.0 + c^2/(-4.0 + c^2)
3 / 2\ c - 3*c*\-4 + c / ------------------ / 2\ c*\-4 + c /
/ 2\ 2*\6 - c / ---------- 2 -4 + c
2 c c -2 + ------ - - 2 c c - 4
4 -2 + ------- 2 -4 + c
/ 2\ -2*\-6 + c / ---------------- (-2 + c)*(2 + c)