%%%
clear all
x0=sqrt(3);
d=2;
Nt=100;

x(1)=x0;t(1)=0;
for ia=2:Nt;
    
    t(ia)=(ia-1)*d;
    x(ia)=exp((1-x(ia-1))*d)*x(ia-1);
    x(ia)=-x(ia-1)+x(ia-1)^3/3;
    
   % y(ia)=1/(1+exp(-t(ia)))
   
end;

 figure(45)
 plot(t,x,'r',t,1*exp(0*t),'--k')
 xlabel('t')
[na,xa]=hist(x,100);
figure(60)
plot(xa,na)