# Decay rate

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1. Nov 6, 2015

### Bita_La

Hi everyone
I have a system of ODE as follows
x1_dot=f1(t)-ax1
x2_dot=f2(t)-ax2
x3_dot=f3(t)-ax3

f1,2,3(t) are unknown nonlinear functions of time, a is constant and unknown, x1,2,3 and their derivatives are given. How can I estimate the parameter a from the given information?
Thanks

2. Nov 6, 2015

### SteamKing

Staff Emeritus
It's not clear what information you are given, besides the form of the equations. Do you have some initial values given which occur at a certain time t ?

3. Nov 6, 2015