/x + y 2*x \ |----- - -----|*(y - x) \ x x - y/ ----------------------- 2 2 x + y
(y - x)*((x + y)/x - 2.0*x/(x - y))/(x^2 + y^2)
/ 2 \ (y - x)*\- 2*x + (x + y)*(x - y)/ ---------------------------------- / 2 2\ x*(x - y)*\x + y /
/ 2 \ (y - x)*\- 2*x + (x + y)*(x - y)/ ---------------------------------- / 2 2\ x*(x - y)*\x + y /