The solution of the differential equation (y+xxy(x+y))dx+(yxy(x+y)−x)dy=0 is
x2y22+tan−1xy=c
x2+y22+tan−1yx2=c
x2+y22+2tan−1xy=c
x2+y2+tan−1x2y=c
ydx−xdy+xxy(x+y)dx+yxy(x+y)dy=0ydx−xdy+(x+y)xy(xdx+ydx)=0ydx−xdyy2+xy+1xydx2+y22=0dx2+y22+dxyxy+1xy=0⇒x2+y22+2tan−1xy=c