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楼主 |
发表于 2024-8-2 07:11
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本帖最后由 APB先生 于 2024-8-2 07:15 编辑
\[0.1{,}\ \ 0.2{,}\ \ \cdots{,}\ \ 0.9=0.1\times9<1\]\[0.01{,}\ \ 0.02{,}\ \ \cdots{,}\ \ 0.99=0.01\times99<1\]\[\cdots\cdots\]\[0.\dot{0}1{,}\ \ 0.\dot{0}2{,}\ \ \cdots{,}\ \ 0.\dot{9}9=0.\dot{0}1\times\dot{9}9<1\]\[\therefore\ \lim\left( 0.9{,}\ \ 0.99{,}\ \ \cdots{,}\ \ 0.\dot{9}9\right)=1\]\[\therefore\ \lim0.9=0.9<1{,}\ \ \lim0.99=0.99<1{,}\ \ \cdots{,}\ \ \lim0.\dot{9}9=0.\dot{9}9<1\]\[1=0.1+0.9=\cdots=0.\dot{0}1+0.\dot{9}9\] |
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