/ 2 \ z - 3 | z | -----*|z + -----| z + 3 \ 3 - z/
/ 2 \ | z | (-3 + z)*|z + -----| \ 3 - z/ -------------------- 3 + z
(-3.0 + z)*(z + z^2/(3.0 - z))/(3.0 + z)
/ 2 \ (-3 + z)*\z + z*(3 - z)/ ------------------------- (3 + z)*(3 - z)
3*z*(-3 + z) --------------- (3 + z)*(3 - z)
-3*z ----- 3 + z
9 -3 + ----- 3 + z