MATLAB: I’m a using matlab for the first time and the code has 2 errors which I don’t know how to remove can you please take a look it is a 14 line code.

code generationerror

funtion sim_system tspan = 0:0.001:50; z0 = [1,0,sqrt(2),0]; [t,z]=ode45(@problem,tspan,z(0)); plot(t,z(:,1)); figure(); end
function zdot = problem(t,z) zdot = zeros(4,1); zdot(1)=z(2); zdot(2)=((2*sin(z(1))+(sin(z(1)-z(3))*z(4)*z(4))+(cos(z(1)-z(3))*sin(z(1)-z(3))*z(2)*z(2))-(cos(z(1)-z(3))*sin(z(3))))/((cos(z(1)-z(3))*cos(z(1)-z(3)))-2)); zdot(3)=z(4); zdot(4)=((-2*sin(z(1)-z(3))*z(2)*z(2))+(2*sin(z(3)))-(cos(z(1)-z(3))*sin(z(1)-z(3))*z(4)*z(4))+(2*cos(z(1)-z(3))*sin(z(1)))/((cos(z(1)-z(3))*cos(z(1)-z(3)))-2));

Best Answer

Ahmed, two things. In the ode45 call replace z(0) by z0 (you need all four initial conditions, but possibly just a typo)
 [t,z] = ode45(@problem,tspan,z0)
And two, close the function problem with an end statement.
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