Services & Resources / Wolfram Forums
MathGroup Archive
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2006

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: solve the following problem

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

In article <edqr42$t4p$1 at>,
 Alexandr Alexandr <a223253100 at> 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 ...


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)    

  • Prev by Date: Re: Null's not null?
  • Next by Date: three parallel methods for one sequence : Hermite like recurance
  • Previous by thread: Re: solve the following problem
  • Next by thread: Using ContourPlot when between x and y variables there is a constriant