A = 2;    % Parameter values for our ODE
y0 = [0 1 0];    % Initial conditions
tspan = [0 30];  % Time interval

[t,y] = ode45('high_order_rhs', tspan, y0, [], A);

plot(t, y(:,1), 'b-', t, y(:,2), 'g-', t, y(:,3), 'r-')