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