Path: news.mathworks.com!not-for-mail
From: <HIDDEN>
Newsgroups: comp.soft-sys.matlab
Subject: Re: Radius of convergence?
Date: Mon, 9 Feb 2009 19:17:02 +0000 (UTC)
Organization: The MathWorks, Inc.
Lines: 8
Message-ID: <gmpvfe$jr3$1@fred.mathworks.com>
References: <gmp919$5sd$1@fred.mathworks.com> <gmpg2v$ba9$1@fred.mathworks.com> <gmpmo1$71h$1@fred.mathworks.com>
Reply-To: <HIDDEN>
NNTP-Posting-Host: webapp-02-blr.mathworks.com
Content-Type: text/plain; charset="ISO-8859-1"
Content-Transfer-Encoding: 8bit
X-Trace: fred.mathworks.com 1234207022 20323 172.30.248.37 (9 Feb 2009 19:17:02 GMT)
X-Complaints-To: news@mathworks.com
NNTP-Posting-Date: Mon, 9 Feb 2009 19:17:02 +0000 (UTC)
X-Newsreader: MATLAB Central Newsreader 1187260
Xref: news.mathworks.com comp.soft-sys.matlab:517144

"Joerg Buchholz" <buchholz@hs-bremen.de> wrote in message <gmpmo1$71h$1@fred.mathworks.com>...
> ......
>  ... I could also ask if there is a way for the Symbolic Math Toolbox to find the nth coefficient c_n of the power series approximation of any given analytical function.
> ......

  When you ask "[Is] there is a way for the Symbolic Math Toolbox to find the nth coefficient c_n of the power series approximation of any given analytical function", strictly speaking the answer is yes, namely using the 'taylor' function.  However, I think that isn't what you meant to ask.  You undoubtedly intended to ask if that coefficient can be expressed as a symbolic function of n so that it could be used in a symbolic expression in the 'limit' function.  I strongly suspect the answer to that question is no.  Finding such a symbolic expression is equivalent to finding a symbolic expression in terms of n for the n-th derivative of a given symbolic expression which I think is beyond the powers of matlab's Symbolic Toolbox.  The function 'diff' (differentiation) accepts only specific values of n and does not generate a symbolic expression involving n.

Roger Stafford