Math Forum http://mathforum.org/kb List of forum topics en Clean output of mathematica http://mathforum.org/kb/thread.jspa?messageID=7935625&tstart=0#7935625 Following code solves the 2nd order differential equation.

s = DSolve[{y''[x] == - a^2 y[x]}, y, x]
t = Reduce[y[0] == 0]]> Dec 11, 2012 7:54:54 PM Dec 11, 2012 7:54:54 PM docpasmon@gmail.com 0