How to represent the followind ODE system in MatLab?

Answer 1

[Star Strider]

Define ‘y’ as ‘x(1)’, ‘k’ as ‘x(2)’, and code it using those substitutions. (I coded it as a one-line anonymous function.)

Remember to include ‘a’ in the argument list, then pass a value for ‘a’ to it in your ODE solver call. See Passing Extra Parameters.

If this is not homework, I can post my solution.

[Cristian Gav]

It's for a work project .Feel free to post the solution if you can.

[Star Strider]

Since it’s not homework, sure!

% % % x(1) = y,   x(2) = k
ODEfcn = @(t,x,a) [0.25*x(1).*(1-x(1)) - 0.0015*x(2) - 0.3*x(1); 0.25*x(1).*(1-x(1)) - 0.0515*x(2)];

ic = [1 1];
tspan = [0 50];
a = 42;                                                     % Substitute Correct Value
[t,y] = ode45(@(t,x)ODEfcn(t,x,a), tspan, ic);

figure
plot(t, y)
grid

It is always appropriate to check it to be certain I transcribed it correctly. Use the appropriate initial conditions (‘ic’) and time interval or vector (‘tspan’). See the documentation for the various functions and for Anonymous Functions for a full explanation.