2 x + 4 ------ 2 x - 4
(x^2 + 4)/(x^2 - 4)
1 - 2/(2 + x) + 2/(-2 + x)
2 2 1 - ----- + ------ 2 + x -2 + x
(4.0 + x^2)/(-4.0 + x^2)
2 4 + x ---------------- (-2 + x)*(2 + x)
(4 + x^2)/((-2 + x)*(2 + x))
8 1 + ------- 2 -4 + x
1 + 8/(-4 + x^2)