Path: news.mathworks.com!not-for-mail From: <HIDDEN> Newsgroups: comp.soft-sys.matlab Subject: Re: how can i solve inline system of equations using fsolve() Date: Sun, 23 Dec 2012 19:13:08 +0000 (UTC) Organization: The MathWorks, Inc. Lines: 8 Message-ID: <kb7l44$t5r$1@newscl01ah.mathworks.com> References: <kb70t7$pgj$1@newscl01ah.mathworks.com> Reply-To: <HIDDEN> NNTP-Posting-Host: www-06-blr.mathworks.com Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Trace: newscl01ah.mathworks.com 1356289988 29883 172.30.248.38 (23 Dec 2012 19:13:08 GMT) X-Complaints-To: news@mathworks.com NNTP-Posting-Date: Sun, 23 Dec 2012 19:13:08 +0000 (UTC) X-Newsreader: MATLAB Central Newsreader 1187260 Xref: news.mathworks.com comp.soft-sys.matlab:785306 "Tian " <tc28@cs.brown.edu> wrote in message <kb70t7$pgj$1@newscl01ah.mathworks.com>... > G = @(k)('[k(:,1) - (4*(x + a*h) + y + h/2*k(:,1) + c * h * k(:,2) - 1)^(0.5); k(:,2) - (4*(x + b*h) + y + d*h*k(:,1) + h/4*k(:,2) -1)^(0.5)]') > > [k, fval] = fsolve(G, [0.0,0.0]) - - - - - - - - - - Your equations can fairly easily be reduced by hand to finding the four roots of a certain quartic equation for which you could use matlab's 'roots' function. Or you could use matlab's 'solve' to do that reducing for you. Perhaps 'solve' might even get the numerical solution for you (provided you furnish the values of x, y, and h.) That would avoid making possibly inappropriate initial estimates for 'fsolve'. Roger Stafford