xset("default");
xset("font",2,3);
xset("window",0);xbasc();
plotframe([3.5,-0.1,4,1],[2,5,0,11],[%f,%f],["(b)","r","Iteres"]);
r=[3.5:0.0005:4];
   deff("y=f(x)","y=r.*x.*(1-x)");
   x=rand(r);
   for i=1:1000,
     x=f(x);
   end;
   for i=1:100,
     x=f(x);
     plot2d(r,x,0,"000");
   end;





