Path: news.mathworks.com!not-for-mail From: <HIDDEN> Newsgroups: comp.soft-sys.matlab Subject: Solving differential equations Date: Sat, 11 Feb 2012 22:10:10 +0000 (UTC) Organization: University of Rhode Island Lines: 9 Message-ID: <jh6p02$k21$1@newscl01ah.mathworks.com> Reply-To: <HIDDEN> NNTP-Posting-Host: www-05-blr.mathworks.com Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Trace: newscl01ah.mathworks.com 1328998210 20545 172.30.248.37 (11 Feb 2012 22:10:10 GMT) X-Complaints-To: news@mathworks.com NNTP-Posting-Date: Sat, 11 Feb 2012 22:10:10 +0000 (UTC) X-Newsreader: MATLAB Central Newsreader 1378413 Xref: news.mathworks.com comp.soft-sys.matlab:757406 I need to solve differential equations: 3 equations: dX/dt = MX-kX dS/dt = DS0 - (MX/Y) dP/dt = AdX/dt + BX the 4th and 5th equations are dM/dX = Mmax.S/kX+S dM/dS = Mmax.S/kX+S So, the first 3 equations are with respect to time and the 4th and 5th equations are with respect to one of the 3 variables that are solved wrt time. If I were to solve only the first 3 equations, I know how to write the code and solve using ODE45. But how do I incorporate the 4th and 5th equations? All of these need to be solved simultaneously. Could you guide me to any help files?