∵cosydx+(1+e^(-x))sinydy=0 ==>dx/(1+(e-x))+sinydy/cosy=0 ==>e^xdx/(1+e^x)-d(cosy)/cosy=0 ==>d(1+e^x)=d(cosy)/cosy ==>ln(1+e^x)=ln|cosy|+ln|C| (C是积分常数) ==>1+e^x=Ccosy又当x=0时,y=π/3∴2=C/2∴C=4故原微分方程的特解是:1+e^x=4cosy