function plotslop
    x=-5:1:5;
    y=x;
    eps=0.1;
    hold on
    for k=1:length(x)
        for m=1:length(y)
            plot([x(k)-eps, x(k)+eps], [-eps*ff(x(k), y(m))+y(m), eps*ff(x(k),y(m))+y(m)])
            plot(x(k),y(m),'r.', 'LineWidth', 0.2)
        end
         axis([x(1)-1, x(length(x))+1,y(1)-1,y(length(y))+1])

    end
    function z=ff(x,y)
        z=y;
    end
end

