"We all" know the soln. to this one: D^2 + aD + bX = 0 A more
realistic in some cases is: D^2 + a(D * D) + bX = 0 ** What's the
soln. for the oscillatory case?
bc been modeling it w/ leapfrog and would like the analytic in
addition to the numerical.
** More complete, but unnecessary and likely very difficult: D^2 +
aD + b(D*D) + c*signum(D)+ dX = 0