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

/* code_begins */

{{{
#Prob 19 - solving a 2nd order DE with boundary conditions
x=var('x')
y=function('y',x)
de=diff(y,x,2)+4*y==0
desolve(de,y,ics=[0,3,-3])
}}}

/* code_ends */

 * '''Solution by''': 
   * <Aniket Basu>, <Mathematical Physicist>, <ISI Kolkata>