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

/* code_begins */

{{{
x = var('x')   
u = function('u',x)   
sol=desolve(diff(u,x,x) + 9*u, [u,x])
print sol
#Here, a PDE is asked to be solved as ODE, treating other variables as parameters
#So, we get the constants 'k1' and 'k2' in the solution as a function of other variables

/* code_ends */

 * '''Solution by''': 
   * Aashita Kesarwani, Student, IIT Roorkee
   * Snehal Mitragotri, Ex-student, IIT Roorkee
   * Tale PrafullKumar, Student, IIT Roorkee