本帖最后由 APB先生 于 2026-3-23 13:21 编辑
\[1\equiv0.1+0.9\equiv0.01+0.99\equiv\cdots\equiv0.\dot{0}1+0.\dot{9}9\]\[1\equiv\frac{1}{10}+\frac{9}{10}\equiv\frac{1}{100}+\frac{99}{100}\equiv\cdots\equiv\frac{1}{1\dot{0}}+\frac{\dot{9}}{1\dot{0}}{,}\ \ \ \ 1\dot{0}=10^{\infty}\]\[\left\{ 0.1{,}\ 0.01{,}\ \cdots{,}\ 0.\dot{0}1{,}\ \cdots\right\}\subset\mathbb{R}\] |