function y=ill(t,x)
a=1;b=0.3;
y=[a*x(1)*x(2)-b*x(1),-a*x(1)*x(2)]';
ts=0:50;
x0=[0.02,0.98];
[t,x]=ode45('ill',ts,x0);
plot(t,x(:,1),t,x(:,2)),grid,pause
plot(x(:,2),x(:,1)),grid on;
end
a=1;b=0.3;
y=[a*x(1)*x(2)-b*x(1),-a*x(1)*x(2)]';
ts=0:50;
x0=[0.02,0.98];
[t,x]=ode45('ill',ts,x0);
plot(t,x(:,1),t,x(:,2)),grid,pause
plot(x(:,2),x(:,1)),grid on;
end