Path: news.mathworks.com!not-for-mail From: <HIDDEN> Newsgroups: comp.soft-sys.matlab Subject: Re: Simple non-linear equation solving question Date: Mon, 13 Feb 2012 05:32:10 +0000 (UTC) Organization: The MathWorks, Inc. Lines: 70 Message-ID: <jha78q$3ph$1@newscl01ah.mathworks.com> References: <jha4b1$os6$1@newscl01ah.mathworks.com> <jha64h$kls$1@speranza.aioe.org> Reply-To: <HIDDEN> NNTP-Posting-Host: www-00-blr.mathworks.com Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Trace: newscl01ah.mathworks.com 1329111130 3889 172.30.248.45 (13 Feb 2012 05:32:10 GMT) X-Complaints-To: news@mathworks.com NNTP-Posting-Date: Mon, 13 Feb 2012 05:32:10 +0000 (UTC) X-Newsreader: MATLAB Central Newsreader 1172347 Xref: news.mathworks.com comp.soft-sys.matlab:757481 Thanks for the response. My Matlab version is 7.10.0 (R2010a). The full code: clear all clc close all x=[-.5:.01:1]; m=-x.^3 + (sin(x)).^2; plot(x,m) clear x x = sym('x'); solve(-x.^3 + (sin(x)).^2) Which provides a plot, and: ans = matrix([[0]]) From the plot, I can see that there is also a solution at about 0.803. Thanks again... "Nasser M. Abbasi" <nma@12000.org> wrote in message <jha64h$kls$1@speranza.aioe.org>... > On 2/12/2012 10:42 PM, Patrick wrote: > > Hi, > > > > I'm trying to solve the following non-linear equation: 0=-x^3 + (sin(x))^2 > > > > EDU>> solve(-x^3+sin(x)^2) > > > > ans = > > > > matrix([[0]]) > > > > By graphing this equation, it appears that there are solutions at 0 and 0.803. What am I doing wrong? > > > > Thanks... > > Which verssion do you have? > > on mine: > > MATLAB Version 7.12.0.635 (R2011a) > > I get > > -------------------- > EDU>> syms x > solve(-x^3+sin(x)^2) > > ans = > > 0 > ---------------------- > > matrix([[0]]) means zero solution also? i..e a vector, which one > entry, and that entry is zero. so same answer I have. > > So, I do not know how you got 0.803 there. What command you used > to plot? Please show complete code you did, not one line. > > --Nasser