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Re: System of differential equations

  • To: mathgroup at smc.vnet.net
  • Subject: [mg128990] Re: System of differential equations
  • From: stephen.p.luttrell at gmail.com
  • Date: Fri, 7 Dec 2012 01:38:53 -0500 (EST)
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I found that converting your input cell to TraditionalForm and then back again to StandardForm - thus causing the terms in the differential equations to be reorganised - made NDSolve work though you now get a "NDSolve::mxst: Maximum number of 10000 steps reached ..." warning message.

Stephen Luttrell
West Malvern, UK

On Thursday, 6 December 2012 09:56:30 UTC, hazem.ab... at gmail.com  wrote:
> Dear all,
>
> I want to solve this system of equations but I always get an error
>
>
>
> NDSolve::ndnum:Encountered non-numerical value for a derivative at t==0
>
>
>
> can any one help me on this
>
>
>
> s=NDSolve[{
>
> ph1''[t]+ph1'[t]+sin[ph1[t]]-mu[t]-mu'[t]==0.005,
>
> ph2''[t]+ph2'[t]+sin[ph2[t]]+mu[t]+mu'[t]==0.005,
>
> 0.2mu'[t]+mu[t]==ph1'[t]-ph2'[t],
>
> ph2[0]==0,
>
> ph1[0]==0,
>
> ph2'[0]==0,
>
> ph1'[0]==0,
>
> mu[0]==0
>
> },
>
> {ph1[t],ph2[t],mu[t]},
>
> {t,0,5000}
>
> ]
>
>
>
> thanks in advance,



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