function [f,g]=ham3chieu (hamso,x);
    %
    [f g]=feval(hamso,x,x);
    [x,y]=meshgrid(x,g);
    [f,g]=feval(hamso,x,y);
    h=figure();
    subplot(1,2,1);
    surf(x,y,g);
    title('ham y');
    subplot(1,2,2);
    surf(x,y,f);
    title('ham f');