1-1+1-1+1-1+1... 这个无穷数列的值是什么？如何证明？ - 知乎
知乎，中文互联网高质量的问答社区和创作者聚集的原创内容平台，于 2011 年 1 月正式上线，以「让人们更好的分享知识、经验和见 …
Why is $1$ not a prime number? - Mathematics Stack Exchange
Why is $1$ not considered a prime number? Or, why is the definition of prime numbers given for integers greater than $1$?
How can 1+1=3 be possible? - Mathematics Stack Exchange
Feb 3, 2021 · Hi, welcome to Math SE! Can you show us the proof you're looking at? There are a lot of false proofs of this sort out …
有问题，就会有答案 - 知乎
知乎，中文互联网高质量的问答社区和创作者聚集的原创内容平台，于 2011 年 1 月正式上线，以「让人们更好的分享知识、经验和见 …
arithmetic - Formal proof for $(-1) \times (-1) = 1$ - Mathematics ...
Is there a formal proof for $(-1) \\times (-1) = 1$? It's a fundamental formula not only in arithmetic but also in the whole of math. Is …
如何打•？ - 知乎
如何在输入法里输入这个符号？Google了很多发现都不对
Why is $x^{-1} = \\frac{1}{x}$? - Mathematics Stack Exchange
Substitute a by 1 and b, c by x, we find both definition of 1 x and x − 1 reduce to the unique y in Y (if exists) such that yx = 1 = xy. As …
足球让球0.5/1什么意思？ - 知乎
把 里面的“/” 理解为将投注额平分。 比如你打算投注10块的让0.5/1， 就是5块买 让0.5 剩下5块买让1 如果让球方净胜1球，那么让0.5 …
"Normalize" values to sum 1 but keeping their weights
40 10 I need to format these numbers so that they form the sum 1, but they should keep their "weight". In this specific case: 40 would …
1/1+1/2+1/3+1/4+……+1/n=？怎么个解法？ - 知乎
红线是n-1到n的割线，绿线是n处的切线 图像上显然，割线的斜率大于切线的斜率。 所以我们有割线的斜率 \dfrac {\ln \left ( n\right) …