Date: Apr 8, 2013 2:21 AM
Author: Bruno Luong
Subject: Re: diff eq

"richard " <richard7893@embarqmail.com> wrote in message <kjrsih$mgb$1@newscl01ah.mathworks.com>...

>
> this is what I am typing into MATLAB:
> function dx = system_ex(t,x)
> dx = zeros(4,1);
> dx(1) = -2.4712*x(1) + 0.005*x(2) + 0.56*x(3)+ 0.1*x(4);
> dx(2) = 0.385*x(1) - 0.1002*x(2)
> dx(3) = 0.002*x(2) - 0.6462*x(3)
> dx(4) = 0.007*a(2) - 0.2042*x(4)
> [T,X] = ode45(@systems_ex,[0 10],[1 0 0 0])
> plot(t,x(:,1))
>


I hope you save system_ex in an mfile and call ode45 on another mfile. You seem to put everything in the same mfile.

Bruno