Let us assume that 
and re-write the problem as follows:
and re-write the problem as follows:
Let's transform it so it can be used in an ode setting:
These are used in the function (vdp1) as follows:
solve this the time interval of [0 10] with initial values of [0.2 0] for x_1, x_2 respectively.
[t,x] = ode45(@vdp1,[0 10],[0.2 0])
plot(t,x(:,1),'-o',t,x(:,2),'-o')
title('Solution with ODE45');
xlabel('Time t');
ylabel('Solution x');
legend('x_1','x_2');
function dxdt = vdp1(t,x)
% ODE
dxdt = [x(2); -2*(x(2)+x(1))];
end
