Re: NDSolve, three 2-d order ODE, 6 initial conditions

*To*: mathgroup at smc.vnet.net*Subject*: [mg115218] Re: NDSolve, three 2-d order ODE, 6 initial conditions*From*: schochet123 <schochet123 at gmail.com>*Date*: Tue, 4 Jan 2011 04:28:13 -0500 (EST)*References*: <ifs30l$oov$1@smc.vnet.net>

In the third ODE you need to have z[t] instead of just z in the expression D[z, {t, 2}] Steve On Jan 3, 10:56 am, michael partensky <parten... at gmail.com> wrote: > Hi, group! > > An attempt to demonstrate a (restricted) analogy between the Bloch > (magnetic resonance) equation and the motion equation for a charged particle > in the magnetic field leads to the following equation: > > ndSol[w_, w0_, w1_, x0_, y0_, z0_, v0x_, v0y_, v0z_, t1_] := > NDSolve[{Cos[w t ] D[x[t], {t, 2}] + Sin[ w t] D[y[t], {t, 2}] - w Sin[w > t] D[x[t], t] + w Cos[w t] D[y[t], t] == (w - w0) ( Sin[w t ] D[x[t],t] - > Cos[w t] D[y[t], t]), > -Sin[w t] D[x[t], {t, 2}] + Cos[w t] D[y[t], {t, 2}] == (w - w0) (Cos[w > t] D[x[t], t] + Sin[w t] D[y[t], t]) + w1 D[z[t], t], > D[z, {t, 2}] == w1 (Sin[w t] D[x[t], t] - Cos[w1 t] D[y[t], t]), > (D[x[t], t] /. {t -> 0} ) == v0x, (D[y[t], t] /. {t -> 0} ) == v0y, (D[z[t], > t] /. {t -> 0}) == v0z, x[0] == x0, y[0] == y0, z[0] == = z0 }, {x[t], y[t], > z[t]}, {t, t1}]; > > Apparently there is an error - u will see the message. Could you please help > catching it? > Thanks > Michael Partenskii