derivative of x/(x^2+y^2)-y^2 with respect to x
Let's perform the differentiation: ddx(xx2 + y2 -y2)
ddx(xx2 + y2) + ddx(-y2)
We differentiate u1 = x and v2 = x2 + y2 using: ddx(u1v2) = ddx(u1)·v2 -u1·ddx(v2)v22
Let's perform the differentiation u1: ddx(x)
1
Let's perform the differentiation v2: ddx(x2 + y2)
ddx(x2) + ddx(y2)
ℹddx(x2) = 2x‖ddx(y2) = 0
2x + 0
2x
You can evaluate the resulted derivative (u1v2)': 1·(x2 + y2) -x·2x(x2 + y2)2
(x2 + y2) -x2·2(x2 + y2)2
-x2 + y2(x2 + y2)2
Then you can resume the derivation:
ℹddx(xx2 + y2) = -x2 + y2(x2 + y2)2‖ddx(-y2) = 0
-x2 + y2(x2 + y2)2 + 0
-x2 + y2(x2 + y2)2
▶Derivative:   y2 -x2(x2 + y2)2