MathGroup Archive 2002

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

Search the Archive

Re: Why can't Mathematica find this root?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg38436] Re: Why can't Mathematica find this root?
  • From: "David W. Cantrell" <DWCantrell at sigmaxi.org>
  • Date: Sun, 15 Dec 2002 02:10:03 -0500 (EST)
  • References: <at4dgq$f1c$1@smc.vnet.net> <at9b6n$pqk$1@smc.vnet.net> <200212130908.EAA03312@smc.vnet.net> <ateq76$92m$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

Daniel Lichtblau <danl at wolfram.com> wrote:
> I did not really understand at first the nature of the question. Now
> that I do I'll take a stab at it. Under Solve>Further Examples>"Getting
> infinite solution sets for some equations" in the Help Browser, there is
> code to do something called "GeneralizeSolve".

Many thanks for pointing this out. I had not see it before.
It answers the question at the end of my previous post in this thread:
"Can anyone suggest a simple way, avoiding human intervention, to have
Mathematica give an equivalent form of the result?"

> It is based on finding
> periodic inverses to various known functions, and takes advantage of the
> fact that Solve will find solutions in terms of these inverse functions.
> It does not quite work directly on your problem for the simple reason
> that e.g. ArcSin[0] will evaluate to 0. So we make it work by solving
> f'[x]==a and substituting a->0 afterward.

(Yes. I had suggested this also.)

[snip of code,...]
> A minor inconvenience is that some solutions may be listed more than
> once e.g. the last two are equivalent if we regard n as ranging over all
> integers.

OTOH, instead of being viewed as an inconvenience, it might be regarded
in some situations as providing valuable information about the
multiplicities of the roots.

David Cantrell

-- 
-------------------- http://NewsReader.Com/ --------------------
Usenet Newsgroup Service              New Rate! $9.95/Month 50GB


  • Prev by Date: Re: Mathematica is NOT ABLE to export proper eps files ?!
  • Next by Date: Determining the size of text in graphics
  • Previous by thread: Re: Re: Why can't Mathematica find this root?
  • Next by thread: Re: Why can't Mathematica find this root?