       Re: solve the following problem

• To: mathgroup at smc.vnet.net
• Subject: [mg69421] Re: solve the following problem
• From: Paul Abbott <paul at physics.uwa.edu.au>
• Date: Tue, 12 Sep 2006 06:52:28 -0400 (EDT)
• Organization: The University of Western Australia
• References: <edqr42\$t4p\$1@smc.vnet.net>

```In article <edqr42\$t4p\$1 at smc.vnet.net>,
Alexandr Alexandr <a223253100 at yahoo.com> wrote:

> How would I solve the following problem with
> Mathematica?
> x'(t) + x(t-1) = 0.

Well, it is easy to verify that

c E^(t ProductLog[-1])

satisfies the equation for arbitrary c as follows,

x'[t] + x[t-1] == 0 /.
x -> Function[t, c E^(t ProductLog[-1])] // FullSimplify

I think you need to specify the problem more completely ...

Cheers,
Paul

_______________________________________________________________________
Paul Abbott                                      Phone:  61 8 6488 2734
School of Physics, M013                            Fax: +61 8 6488 1014
The University of Western Australia         (CRICOS Provider No 00126G)
AUSTRALIA                               http://physics.uwa.edu.au/~paul

```

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