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

/* code_begins */

{{{
#2.4-1
x=var('x')
y=function('y',x)
y=e^(-x)+e^(2*x)
de=diff(y,x,2)+3*diff(y,x,1)
print de
}}}

/* code_ends */

 * '''Solution by''': 
   *K B Patil,lecturer,SIGCOE KOPERKHAIRANE NAVI MUMBAI.