Path: news.mathworks.com!not-for-mail From: "Ender " <jr147@msstate.edu> Newsgroups: comp.soft-sys.matlab Subject: Re: eigen values equation Date: Fri, 19 Feb 2010 19:28:06 +0000 (UTC) Organization: Mississippi State University Lines: 57 Message-ID: <hlmoo6$eqe$1@fred.mathworks.com> References: <hlmelk$jd9$1@fred.mathworks.com> <hlml7p$rgm$1@fred.mathworks.com> Reply-To: "Ender " <jr147@msstate.edu> NNTP-Posting-Host: webapp-02-blr.mathworks.com Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Trace: fred.mathworks.com 1266607686 15182 172.30.248.37 (19 Feb 2010 19:28:06 GMT) X-Complaints-To: news@mathworks.com NNTP-Posting-Date: Fri, 19 Feb 2010 19:28:06 +0000 (UTC) X-Newsreader: MATLAB Central Newsreader 1035766 Xref: news.mathworks.com comp.soft-sys.matlab:609838 I don't quite understand what you are saying here: > For s = solve(eq), you can take each solution and substitute lambda = 0 > with the subs command to get your "variable." Also, MATLAB did not factor the equation in the form that I am looking for. After typing in eq2 MATLAB outputs: eq2 = -1/8*lamda*(8*lamda^2-5) That is not the form that I am looking for. Also, whenever I type lamda = 0 then type in any of my equations MATLAB does not give me the results minus the lamda variable --Ender-- Alan Weiss <aweiss@mathworks.com> wrote in message <hlml7p$rgm$1@fred.mathworks.com>... > Ender wrote: > > I have a coding problem that I need help with. > > > > I am trying to write code that displays the value of a determinant with > > eigen values but I need all the equation as simplified as possible then > > I need MATLAB to store the value of the constant in that equation in a > > variable. > > > > Here is my example: > > > > syms lamda > > > > % Make the identity matrix > > Ident_matrix = lamda*eye(3); > > > > A = [0,-.75,0;-0.75,0,0.25;0,0.25,0]; > > > > Result = A-Ident_matrix; > > > > % Find the rho(T-j) value > > > > eq = det(Result) > > > > The form that I want is: > > -lamda*(lamda^2-0.625) > > > > Then I would like MATLAB to store the 0.625 in a variable. > > > > I am not sure where in the help menu to go to figure out how to do this. > > --Ender-- > > You are really close. See what happens with the following statements: > s = solve(eq) > and > eq2 = factor(eq) > > For s = solve(eq), you can take each solution and substitute lambda = 0 > with the subs command to get your "variable." > > Alan Weiss > MATLAB mathematical toolbox documentation