math - Simple MATLAB/Octave simulation -

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this should simple question has experience in area, i'm still new this.

i have following system (or here image better resolution):

alt text http://img199.imageshack.us/img199/2140/equation1.png

given following input:

u = min(2 - t/7.5, 2*(mod(t, 2) < 1));

i need plot output of system y.

i describing system following function:

function xprime = func(t, x)     u = min(2 - t/7.5, 2*(mod(t, 2) < 1));     xprime = [         x(2);         x(3);         0.45*u - 4*x(3)^2 - x(2)*x(1) - 4*x(2) - 2*x(1);         x(5);         sin(t) - 3*x(5)*x(1);     ];

and simulating ode23, this:

[tout, xout] = ode23(@func, [0 15], [1.5; 3; -0.5; 0; -1])

after simulation, xout have 5 columns. question is: how know 1 output of y system?

edit: ok, put simple, i'd plot solution this:

a = 1 % goes here? 1, 2, 3, 4 or 5? plot(tout, xout(:,a))

the 1 corresponds y, appears x(1), of course.

if compare code equations, can see x(1) appears in code every place y appears in equations. best guess.


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