Path: news.mathworks.com!not-for-mail From: <HIDDEN> Newsgroups: comp.soft-sys.matlab Subject: solving equations with a matrix Date: Sun, 4 Apr 2010 03:12:06 +0000 (UTC) Organization: The MathWorks, Inc. Lines: 17 Message-ID: <hp9026$cnj$1@fred.mathworks.com> Reply-To: <HIDDEN> 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 1270350726 13043 172.30.248.37 (4 Apr 2010 03:12:06 GMT) X-Complaints-To: news@mathworks.com NNTP-Posting-Date: Sun, 4 Apr 2010 03:12:06 +0000 (UTC) X-Newsreader: MATLAB Central Newsreader 1776786 Xref: news.mathworks.com comp.soft-sys.matlab:623247 Hi, I am trying to solve two 3 term equations with matrices the first one is not a problem as it is linear. The equations are Ra+Rb=250 Rb+Rc=500 Rc+Ra=300 But the second one has terms which are to the power of negative 1, and I don't know how or indeed if they can be setup in a matrix to be solved. The equations are (Z1^-1+(Z2+Z3)^-1)^-1=300 (Z2^-1+(Z1+Z3)^-1)^-1=250 (Z3^-1+(Z1+Z2)^-1)^-1=500 The equations are used in 3 phase power engineering, the one above is for a delta model, the one above that is for a star model The one I'm not having a problem with is for a star model, and its values can be used to find the values of the above equations by inserting them into another set of equations Z1=Ra+Rc+((Ra*Rc)/Rb) Z2=Ra+Rb+((Ra*Rb)/Rc) Z3=Rb+Rc+((Rb*Rc)/Ra) I can solve the delta model directly with a calculator but I would perfer to be able to show my working for exams. So my question is can the second set of equations be solved with matrices, and if so how?? Cheers Darryl