y^3y''-1=0,微分方程通解

2个回答

  • 令y'=p(y),y''=(dp/dy)(dy/dx)=(dp/dy)p

    原方程化为:y^3*(dp/dy)p-1=0,分离变量得:pdp=dy/y^3

    两边积分得:1/2p^2=-(1/2)y^(-2),即p^2=-1/y^2+C1

    则(dy/dx)^2=C1-1/y^2

    dy/dx=√(C1-1/y^2)

    ydy/√(C1y^2-1)=dx

    两边积分得:√(C1y^2-1)/C1=x+C2

    即:√(C1y^2-1)=C1x+C3