ناوەندی ھارمۆنیک

${\displaystyle H={\frac {n}{{\frac {1}{x_{1}}}+{\frac {1}{x_{2}}}+\cdots +{\frac {1}{x_{n}}}}}={\frac {n}{\sum \limits _{i=1}^{n}{\frac {1}{x_{i}}}}}=\left({\frac {\sum \limits _{i=1}^{n}x_{i}^{-1}}{n}}\right)^{-1}.}$

${\displaystyle H={\frac {2x_{1}x_{2}}{x_{1}+x_{2}}}.}$ 

${\displaystyle A={\frac {x_{1}+x_{2}}{2}}}$ 

${\displaystyle G={\sqrt {x_{1}x_{2}}},}$ 

${\displaystyle H={\frac {G^{2}}{A}}=G\cdot \left({\frac {G}{A}}\right).}$