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 > > >