这个就仅仅求导就好了
3、(1) y=(C1+C2x)e^xy'=C2e^x+(C1+C2x)e^x=(C1+C2+C2x)e^xy(0)=0(C1+C2×0)e^0=0C1=0y'(0)=1(0+C2+C2×0)e^0=1C2=1(2) y=C1cosx+C2sinxy'=-C1sinx+C2cosxy(0)=1C1cos0+C2sin0=1C1=1y'(0)=3-C1sin0+C2cos0=3C2=3