compute $\lim_{n\to \infty} \sqrt{n}(\sqrt{n+1}-\sqrt{n})$

Question

Possible Duplicate:
Limits: How to evaluate $\lim\limits_{x\rightarrow \infty}\sqrt[n]{x^{n}+a_{n-1}x^{n-1}+\cdots+a_{0}}-x$
Calculate $\displaystyle\lim_{n\to{+}\infty}{(\sqrt{n^{2}+n}-n)}$

how should I approach the following limit? $$\lim_{n\to \infty} \sqrt{n}(\sqrt{n+1}-\sqrt{n})$$

Answer 1

A start: Multiply by $\dfrac{\sqrt{n+1}+\sqrt{n}}{\sqrt{n+1}+\sqrt{n}}$.