for k=1:50
  0;
  r(k) = .1*k;
  
x0 = rand;

for n=1:1000
x(n) = exp(-r(k)*x0);
%x(n) = r(k).*tan(x0);
%x(n) = r(k).*cos(x0);
%x(n)=r(k).*x0.*(1-x0);
%x(n) = r(k).*x0^2/(1 + x0^2);
x0=x(n);
end

for n=990:1000
  plot(r(k),x(n),'*');
  hold on
  
end

end