可以留下一个优美的不等式吗？
$H_{n}=\frac{n}{\sum \limits_{i=1}^{n}\frac{1}{x_{i}}}=\frac{n}{\frac{1}{x_{1}}+ \frac{1}{x_{2}}+ \cdots + \frac{1}{x_{n}}} $$G_{n}=\sqrt[n]{\prod \limits_{i=1}^{n}x_{i}}= \sqrt[n]{x_{1}x_{2}\cdots x_{n}}$$A_{n}=\frac{1}{n}\sum \limits_{i=1}^{n}x_{i}=\frac{x_{1}+ x_{2}+ \cdots +x_{n}}{n} $$Q_{n}=\sqrt{\sum \limits_{i=1}^{n}x_{i}^{2}}=\sqrt{\frac{x_{1}^{2}+ x_{2}^{2}+ \cdots + x_{n}^{2}}{n}}$$H_{n} \leq G_{n}\leq A_{n}\leq Q_{n}$