two coupled differential equations

*To*: mathgroup at smc.vnet.net*Subject*: [mg121182] two coupled differential equations*From*: Mark.Musters at leadpharma.com*Date*: Sat, 3 Sep 2011 08:04:09 -0400 (EDT)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com

Hi I have two coupled differential equations, for which I would like to derive the parameter values by fitting them on a data set. The differential equations have the following form: x1'[t] == -k1*x1[t] x2'[t] == k2*x1[t]-k3*x2[t]/(k4+x2[t]) The experimental time-series data has the following form t== {0,1,4,8,12,24} x1 == {10,9,5,3,1,.1} x2 == {2,4,5,7,9.1,11} The examples I can find with FindFit are aimed at a single differential equation, so I was wondering how I can assign the data to the corresponding state variable and perform a parameter estimation to get an estimate for parameters k1, k2, k3 and k4. It would help me a lot. Many thanks in advance, Mark