2.求下列微分方程的通解.-|||-(1) y''-y'+y=0 ;-|||-(2) y''+2y'-3y=0 ;-|||-(3) y''-8y'+16y=0 ;-|||-(4) y''+y=0 ;-|||-(5) ''-y=cos x ;-|||-(6) ''+4y'+4y=(e)^-2x ;-|||-(7) ''+2y'+2y=2(e)^-xsin x ;-|||-(8) ^11-5y'+6y=(x)^2(e)^x-x(e)^3x ;-|||-(9) ^2y''+4xy'+2y=0(xgt 0) ;-|||-(10) ^3(y)^111+(x)^2(y)^11-4xy'=3(x)^2 -