CRTANJE

[x1,x2] = meshgrid(-10:0.1:10,-10:0.1:10);
[m, n] = size(x1);
z = zeros(m, n);
for i = 1: m
    for j = 1:n
        z(i, j) = y([x1(i, j), x2(i, j)]);
    end
end
surf(x1, x2, z);hold on;
scatter3(x(1), x(2), fx, 'Xr'); hold off;