    u = eps / 2;
    fprintf('u = %.37e\n', u);
    x = (1 + u) + u;
    y = 1 + (u + u);
    fprintf('x = (1+u)+u = %.52e\n', x);
    fprintf('y = 1+(u+u) = %.52e\n', y);
    fprintf('y-x = %.36e\n', y - x);

    a = 2.0;
    b = 3.0;
    x = sqrt(sqrt(a) + sqrt(b) - sqrt(a + b + 2 * sqrt(a * b)));
    fprintf('a = %.5e b = %.5e\n', a, b);
    fprintf('sqrt(sqrt(a)+sqrt(b)-sqrt(a+b+2*sqrt(a*b))) = %.12e\n', x);