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Re: Solving the system with inexact coefficients

  • To: mathgroup at smc.vnet.net
  • Subject: [mg99387] Re: [mg99335] Solving the system with inexact coefficients
  • From: Desana <incolaster at gmail.com>
  • Date: Mon, 4 May 2009 06:02:52 -0400 (EDT)
  • References: <30708295.1241344271268.JavaMail.root@n11>

FindRoot didn't work either, but Ted Ersek's RootSearch package worked
perfectly =)
David, thank you very much
Desana

On Sun, May 3, 2009 at 2:11 PM, David Park <djmpark at comcast.net> wrote:

> It looks like something you have to use FindRoot on. Or better yet Ted
> Ersek's RootSearch package from MathSource at the WRI site. (With changes
> in
> 7.0.1 RootSearch now gives a warning message that can usually be ignored.
> It
> is too bad because RootSearch is much better than FindRoot for root
> searching in 1-dimension.)
>
>
> David Park
> djmpark at comcast.net
> http://home.comcast.net/~djmpark/
>
>
>
> From: Desana [mailto:incolaster at gmail.com]
>
>
> Hello,
> this is my problem : I've got cca 40 sinusoidal waves ( e.g. 0.118149
> Cos[25.1013 t]) and after superposition I get irregurar wave record.
> I'm trying to see how many waves I have in certain interval by finding
> how many zero crossings there are:
>
> Reduce[Total[Subscript[\[Eta], i]] == 0 && 0 < t < 60, t]
>
> but I couldn't because "Reduce was unable to solve the system with
> inexact coefficients"
>
> What's the problem?  What does it mean?
> Can I find intersection between my wave and x-axis in any other wave?
> Perhaps graphically ?
>
> Thank you,
> student Desana
>
>
>


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