10 2017 档案

摘要：http://note.youdao.com/noteshare?id=ce9c630004ba3b2d24e097e039519db6 阅读全文

摘要：At P985 of the book, says But there are cuts that are not determined by rational numbers. If we put into the first class all negative rational numbers and all positive ones whose squares are less th... 阅读全文

摘要：有理数的阿基米德性质 任何有理数$r={\displaystyle \frac{p}{q}}\le |p|$（这里$p$和$q$都是整数并且$q\ne 0$），因为$r={\displaystyle \frac{p}{q}}\le {\displaystyle \frac{|p|}{|q|}}\le {\displaystyle \frac{|p|}{1}}=|p|$，可知 对于任何有理数 阅读全文