Let $g:(1,+\infty)\rightarrow \mathbb{R}$, differentiable, such that $|g'(x)|\leq \frac{1}{x}$ for all $x>1$. Show that
$$\lim_{x\rightarrow +\infty}\left(g(x+\sqrt{x})-g(x)\right)=0.
$$
Seems like the mean value theorem is useful. However, not sure how to prove the fact.
Remark:
The hints says that only proving
$$\lim_{x\rightarrow +\infty}|g(x+\sqrt{x})-g(x)|=0.
$$
won't suffice.
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