#unsolved
#prob:-7
x = var('x') 
k = var('k') 
y = function('y',x)
sol=desolve(diff(y,x,x) + k*y - exp(-k*x), [y,x])
sol
# This was a first order differential equation, which was solved by sage. I made it a second order differential eqn (simply by substituting the first order derivative by second order derivative). Sage prompted  us "Is k positive,negative or zero"

SageDays/Kreyszig-1.6-7 (last edited 2010-08-11 11:02:20 by Aashita)