求方程xdy+dx=e^y dx的通解

3个回答

  • xdy+dx=e^y dx

    xdy=(e^y-1)dx

    dy/(e^y-1)=dx/x

    [-(e^y-1)+e^y]dy/(e^y-1)=dx/x

    -dy+e^ydy/(e^y-1)=dx/x

    ∫[-1+(e^y/(e^y-1)]dy=∫1/x dx+c1

    -y+ln(e^y-1)=lnx+ln(e^c1)

    -y+ln(e^y-1)=lncx

    -y=lncx-ln(e^y-1)

    y=ln(e^y-1)-lncx

    =ln[(e^y-1)/cx]

    e^y=(e^y-1)/cx

    e^y*cx=e^y-1

    e^y-1=Cxe^y 所以结果正确.