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