||'''Book'''|| Advanced Engineering Mathematics ||
 ||'''Author'''|| Erwin Kreyszig ||
 ||'''Edition'''|| 8th Edition ||

/* code_begins */

{{{
x=var('x')#3.  
y=function('y',x)
DE=diff(y,x,x)+2*diff(y,x)+y-exp(-x)*cos(x)
desolve(DE,[y,x])
 
}}}

/* code_ends */

 * '''Solution by''': 
   * <Manjusha S. Joshi>, <Lecturer>, <Bhaskaracharya Institute in Mathematics, Pune>