a*a b ---*(a - b) + ----- b b - a
2 b a *(a - b) ----- + ---------- b - a b
b/(b - a) + a*a*(a - b)/b
2 2 b + a *(a - b)*(b - a) ----------------------- b*(b - a)
2 2 2 - b + a *(a - b) ------------------ b*(a - b)
/ 2 \ / 2 \ \b + a - a*b/*\a - b - a*b/ ----------------------------- b*(a - b)
4 2 4 2 2 a - b - b - b - 2*a + ------------ - a*b 2 - b + a*b