clear all; close all;
% solve and plot the Henon map, including stable and unstable manifolds:
% x(n+1)= x(n)+y(n+1)
% y(n+1)=y(n)+ksin(x(n))

% parameter:
k=0.576; 
N=500;
twopi=pi*2;
% initial conditions:
x(1)=6.2; y(1)=-0.2;
for n=1:N
  y(n+1)=y(n)+k*sin(x(n));
  x(n+1)=x(n)+y(n+1);
  x(n+1)=mod(x(n+1),twopi);
end
plot(x,y,'.')
title('Standard map')
xlabel('x')
ylabel('y')