function [xi,y]=divdifplot(x,F)
     len=length(x);
	xi=linspace(x(1),x(len),50)';
        y=zeros(50,1);


	for i=1:len
	  p=ones(50,1);
	  for j=1:(i-1)
            p=p.*(xi-x(j));
          end
          y=y+F(i,i).*p;
        end


end
