global alpha
global beta
global gamma
global delta
alpha = 20;
beta = 0.1;
gamma = 2;
delta = 0.001;
[T,Y] = ode45('predator_prey',[0,5], [1000,100]);
plot(T,Y(:,1),T,Y(:,2))
hold
plot(T,zeros(size(T,1),1),'LineStyle','none','Marker','+',...
'MarkerEdgeColor','red','Markersize',4);
size(T)
