Which of the following $u=\sqrt{c+1} - \sqrt{c}$ and $v=\sqrt{c} - \sqrt{c-1}$ is greater? If
$$u=\sqrt{c+1} - \sqrt{c}$$
and 
$$v=\sqrt{c} - \sqrt{c-1}$$
then, which among $u$ and $v$ is greater?
Please help without substituting values.

Note that $\sqrt x$ is concave function, so $$2\sqrt x \gt \sqrt {x-1} + \sqrt {x+1}$$
