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



/* code_begins */

{{{
x = var('x')
y = function('y',x)
DE = diff(y,x,x) + y
a=desolve(DE, y,x)
print a
print
# validating the output
s= 1*cos(x) + 1*sin(x)  #placing a=1;  b=1;
diff(s,x,x) + s
}}}
{{{
}}}
 * '''Solution by''':
  * Ankur Khurana , Student, ITM Gurgaon
  * Gaurav Luthra, Student, KIIT Gurgaon