       problems with NDSolve

• To: mathgroup at smc.vnet.net
• Subject: [mg131110] problems with NDSolve
• From: Axel Sielaff <axel.sielaff at googlemail.com>
• Date: Wed, 12 Jun 2013 05:37:32 -0400 (EDT)
• Delivered-to: l-mathgroup@mail-archive0.wolfram.com
• Delivered-to: l-mathgroup@wolfram.com
• Delivered-to: mathgroup-outx@smc.vnet.net
• Delivered-to: mathgroup-newsendx@smc.vnet.net

```Hi,

I'm new in Mathematica and have a problem you can maybe help me with. I try to solve the differential equation given by T. G. Myers and J. P. F. Charpin (http://dx.doi.org/10.1063/1.3155185) as follows:

rho  = 1700
g = 9.81
sigma = 0.00001
c = rho g / sigma
z0 = 0.1
sol = NDSolve[{x'[t] ==
c (z0 - z[t]) - tan[x[t]]/(r Sqrt[1 + tan[x[t]]^2]) ,
y'[t] == cos[x[t]], z'[t] == sin[x[t]], x == 0.0001, y == 0,
z == 0}, {x[t], y[t], z[t]} , {t, 0, 1} ]

I get this result and don't know what to do.

NDSolve::ndnum: Encountered non-numerical value for a derivative at t == 0.`. >>
NDSolve[{Derivative[x][
t] == -(tan[x[t]]/(r Sqrt[1 + tan[x[t]]^2])) +
1.6677*10^9 (0.1 - z[t]), Derivative[y][t] == cos[x[t]],
Derivative[z][t] == sin[x[t]], x == 0.0001, y == 0,
z == 0}, {x[t], y[t], z[t]}, {t, 0, 1}]

Do you have any ideas?
Thanks

```

• Prev by Date: Re: ListPlot3d and ListDensityPlot
• Next by Date: Re: a trivial task?
• Previous by thread: Re: System Modeler and Mathematica 9
• Next by thread: Re: problems with NDSolve