特征方程r^2+2r+1=0r=-1(二重根蚂冲)通解y=(C1+C2x)e^(-x)y(0)=4代入得亏并C1=4y=(4+C2x)e^(-x)y'=(C2-4-C2x)e^(-x) y'(0)=-2代入得C2=2所以闷空歼y=(4+2x)e^(-x)
