plotting the solutions of a differential system with numerical ways

Hi, i'm trying to plot the solutions of a differential system with a numerical method, i don't know how to do this, does anyone know how to do in matlab with an example ?

This is my system:

dx/dt=((3x+2)/(5y+x)) +3*x dy/dt=3*x*y-5y

Thanks you very much !!!

Answer 1

[Mischa Kim]

Yep, take a look:

function my_EOM()
IC       = [-1 -1];
[t,qsol] = ode45(@EOM,[0 1],IC);
plot(t,qsol)
xlabel('t')
ylabel('x, y')
grid
end

function dqdt = EOM(~,q)
x    = q(1);
y    = q(2);
dqdt = [((3*x + 2)/(5*y + x)) + 3*x; ...
          3*x*y - 5*y];
end

[abc abc]

Thanks a lot it works ;)

Answer 2

[Azzi Abdelmalek]

start_time=0
final_time=10
in=[1 ;0]; %initials conditions
[t,y] = ode45(@myfcn,[start_time final_time],in);
plot(t,y)

Where myfcn is a function

function dy=myfcn(t,y)
dy=zeros(2,1)
dy(1)=(3*y(1)+2)/(5*y(2)+y(1))+3*y(1)
dy(2)=3*y(1)*y(2)-5*y(1)

[abc abc]

Thanks a lot it works ;)