
- abstract algebra - Prove that 1+1=2 - Mathematics Stack Exchange- Jan 15, 2013 · Possible Duplicate: How do I convince someone that $1+1=2$ may not necessarily be true? I once read that some mathematicians provided a very length proof of $1+1=2$. Can … 
- Why is $1/i$ equal to $-i$? - Mathematics Stack Exchange- May 11, 2015 · 11 There are multiple ways of writing out a given complex number, or a number in general. Usually we reduce things to the "simplest" terms for display -- saying $0$ is a lot … 
- Formal proof for $ (-1) \times (-1) = 1$ - Mathematics Stack …- Jun 13, 2020 · 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 there a proof for it or is it just assumed? 
- What is the value of $1^i$? - Mathematics Stack Exchange- Aug 30, 2010 · There are infinitely many possible values for $1^i$, corresponding to different branches of the complex logarithm. The confusing point here is that the formula $1^x = 1$ is … 
- 1/1+1/2+1/3+1/4+……+1/n=?怎么个解法? - 知乎- 两边求和,我们有 ln (n+1)<1/1+1/2+1/3+1/4+……+1/n 容易的, \lim _ {n\rightarrow +\infty }\ln \left ( n+1\right) =+\infty ,所以这个和是无界的,不收敛。 
- 为什么 1 不能被认为是质数? - 知乎- 质数就是“只能被1和它本身整除”的自然数。 然而,我们必须在此基础之上增加一条警告,宣称数字1不是质数,这简直就像马后炮一样。 
- 知乎 - 有问题,就会有答案- 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、经验和见解,找到自己的解答」为品牌使命。 
- Word,插入多级列表,但是改了1.1,第二章的2.1也变成1.1,随着 …- 注1:【】代表软件中的功能文字 注2:同一台电脑,只需要设置一次,以后都可以直接使用 注3:如果觉得原先设置的格式不是自己想要的,可以继续点击【多级列表】——【定义新多级 … 
- factorial - Why does 0! = 1? - Mathematics Stack Exchange- Intending on marking as accepted, because I'm no mathematician and this response makes sense to a commoner. However, I'm still curious why there is 1 way to permute 0 things, … 
- 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、经验和见解,找到自己的解答」为品牌使命。