From: "Sebastian Nowoisky" <nowoisky@fh-brandenburg.de>
Path: news.mathworks.com!newsfeed-00.mathworks.com!webcrossing
Newsgroups: comp.soft-sys.matlab
Subject: Re: Polynomial roots
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Date: Thu, 7 Sep 2006 05:31:51 -0400
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Hi Pawel,

you schould write the function in Matrixform
like this:

x^3 -3ix^2 +ix -1
c=[1 -3i i -1]

to get the roots of this function use the roots command

roots(c)

ans =

  -0.0020 +16.6079i
  -0.0024 -13.6079i
   0.0044 + 0.0000i

The next MATLAB function, which I remember is the fzero command.

Hope this example help, let me know.

Best regards

Sebastian Nowoisky

 Pawel wrote:
>
>
> Hello,
>
> I am trying to find roots of a polynomial of the form:
>
> (1-d*x^(-1))*(1-conj(d)*x)-b^2=0
>
> d is complex number,
> b is real number,
>
> The main problem is how to make Matlab interpret properly orders of
> the polynomial - some of them are negative some positive.
>
> Thanks for any help.
>
> Pawel