2025-3-5-我学了什么数学?

	![{\displaystyle H_{n}={\dfrac {n}{\displaystyle \sum _{i=1}^{n}{\dfrac {1}{x_{i}}}}}={\dfrac {n}{{\dfrac {1}{x_{1}}}+{\dfrac {1}{x_{2}}}+\cdots +{\dfrac {1}{x_{n}}}}}}]

![{\displaystyle A_{n}={\dfrac {\displaystyle \sum _{i=1}^{n}x_{i}}{n}}={\dfrac {x_{1}+x_{2}+\cdots +x_{n}}{n}}}]

![{\displaystyle G_{n}={\sqrt[{n}]{\prod _{i=1}^{n}x_{i}}}={\sqrt[{n}]{x_{1}x_{2}\cdots x_{n}}}}]

![{\displaystyle Q_{n}={\sqrt {\dfrac {\displaystyle \sum _{i=1}^{n}x_{i}^{2}}{n}}}={\sqrt {\dfrac {x_{1}^{2}+x_{2}^{2}+\cdots +x_{n}^{2}}{n}}}}]