d/(dx) arctan(y/x) = 1/(1 + (y/x)^2) * (d/dx y/x)ddxarctan(yx)=11+(yx)2⋅(ddxyx)
d/(dx) arctan(y/x) = 1/(1 + (y^2/x^2)) * (- y/x^2 * dy/dx)ddxarctan(yx)=11+(y2x2)⋅(−yx2⋅dydx)
d/(dx) arctan(y/x) = - x^2/(x^2 + y^2) * y/x^2 * dy/dxddxarctan(yx)=−x2x2+y2⋅yx2⋅dydx
d/(dx) arctan(y/x) = - y/(x^2 + y^2) dy/dxddxarctan(yx)=−yx2+y2dydx