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