amp;(x2+y2)dx−5xydy=0amp;dxdy=5xyx2+y2amp; Let y=vxamp;dxdy=v+xdxdvamp;V+xdxdv=5v1+v2amp;xdxdv=5v1+v2−5v2
amp;81∫1−4v28×5vdv=∫xdxamp;8−5ln1−4v2=ln∣x∣+lncamp;⇒85lnx2x2−4y2+ln∣x∣=lncamp;x2x2−4y25/8∣x∣=camp;∣x∣41x2−4y25/8=c∵y(1)=0⇒c=1
amp;⇒x2−4y25/8=∣x∣41amp;x2−4y25=x2