From help-octave-request at bevo dot che dot wisc dot edu  Sat Jul  5 12:12:34 1997
Subject: Re: Root finding procedure?
From: Heber Farnsworth <farnswor at cob dot ohio-state dot edu>
To: Thomas Hoffmann <hoffmann at ehmgs2 dot et dot tu-dresden dot de>
cc: help-octave at bevo dot che dot wisc dot edu
Date: Sat, 5 Jul 1997 13:12:26 -0400 (EDT)

The thing that comes to mind is fsolve.  Write a m-file which takes x as 
an argument and return det(H).  Use fsolve and it will return the value 
of x that makes det(H) as close to zero as possible.  Of course there 
will be a problem with multiple roots and so the answer you get will 
depend on the starting value you give to fsolve.  I don't know of one 
that returns all the roots.

On Fri, 4 Jul 1997, Thomas Hoffmann wrote:

> I am looking for octave- or matlab-code, that allows me to find the
> roots of the polynomial of x that results from det(H)=0, where the Hij
> are polynomials in x theirself.
> E.g.: find the roots x for
> 
>        3x-4    2x+9
> det (                 ) = 0
>        -x+22   4x-11
> 
> I can program such a procedure myself (with successive convolution),
> but this problem seems standard enough to me, that there could be a
> procedure out there in octave-land. 
> Any hints?
> 
> Thomas Hoffmann.
>