解:(1)令y=xt,则y'=xt'+t 代入原方程,得y'=(y/x)ln(y/x) ==>xt'+t=tlnt ==>xt'=t(lnt-1) ==>dt/[t(lnt-1)]=dx/x ==>d(lnt-1)/(lnt-1)=dx/x ==>ln│lnt-1│=ln│x│+ln│C│ (C是积分常数) ==>lnt-1=Cx ==>lnt=Cx+1 ==>ln(y/x)=Cx+1 ==>lny=lnx+Cx+1 故原方程中物斗的通解是lny=lnx+Cx+1 (C是积分常数). (2)∵(x²+y²)dx-xydy=0 ==>(2/x³)(x²+y²)dx=2ydy/x² (等式两端同乘2/x³) ==>2ydy/x²-2y²dx/x³=2dx/x ==>d(y²/x²)=2dx/x ==>y²/x²=ln(x²)+C (C是积卖磨分常数) ==>y²=x²[ln(x²)+C] ∴原方蚂差程的通解是y²=x²[ln(x²)+C] (C是积分常数)。
标签:通解,齐次,方程