Re: NDSolve from negative to positive time

*To*: mathgroup at smc.vnet.net*Subject*: [mg89142] Re: NDSolve from negative to positive time*From*: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>*Date*: Tue, 27 May 2008 07:13:09 -0400 (EDT)*Organization*: Uni Leipzig*References*: <g1dhsu$9l7$1@smc.vnet.net>*Reply-to*: kuska at informatik.uni-leipzig.de

Hi, and just say that instead of sol = NDSolve[{x''[t] + \[Gamma]*x'[t] + x[t] == Cos[t], x[0] == 1, x'[0] == 0} /. \[Gamma] -> 0.05, x[t], {t, 0, 8 Pi}] you wish to solve sol = NDSolve[{x''[t] + \[Gamma]*x'[t] + x[t] == Cos[t], x[0] == 1, x'[0] == 0} /. \[Gamma] -> 0.05, x[t], {t, -8 Pi, 8 Pi}] does not help ?? Regards Jens Allen Robnett wrote: > The answer to my question may be trivial, but I have not found it. I am dealing with the orbits in a three-body problem. I have written equations which do a beautiful job of 3D plotting the results from t=0 to any positive time. The only boundary conditions available are at t=0. I am able to get the correct 3D plot for negative time if I reverse all of the velocities at t=0. I assume that I can then get a plot that combines the two into one plot from negative time to positive time. But this seems very "klutsy" and I believe that Mathematica must provide a sophisticated way to get the results in a single operation. Any suggestions? > > Allen Robnett >