       Re: Differential Equations system

• To: mathgroup at smc.vnet.net
• Subject: [mg6257] Re: [mg6248] Differential Equations system
• From: seanross at worldnet.att.net
• Date: Mon, 3 Mar 1997 01:29:14 -0500
• Sender: owner-wri-mathgroup at wolfram.com

```ISO-8859-2?Q?Ryszard_Wi=B6niowski wrote:
>
> How I can solve the following equations system:
>
> {y''[t]==-g-a*y'[t]+b*x'[t],
>  x''[t]==-a*x'[t]
> }
>
> or this:
> {
>   y''[t]==-g-(a/y[t])*y'[t],
>   x''[t]==-a/y[t]*x'[t]
> }
>
> Richard

I think you need to re-state your question.  If y''[t]= and is a
constant, then you have a parabola.  If (whatever), then
(whatever) is identically zero.  The answer to the first system is that
x and y are constants.  The answer to the second Is that y is a constant
and x is identically zero.  I am guessing, though, that that is not what
you intended.  Remember that there is no substitute for pencil and
paper.  Before attempting solution on the computer, do the best you can
to reduce the problem algebraically.

```

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