- 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。知乎凭借认真、专业、友善的社区氛围、独特的产品机制以及结构化和易获得的优质内容，聚集了中文互联网科技、商业、影视
- What does $QAQ^{-1}$ actually mean? - Mathematics Stack Exchange
1 $\begingroup$ When one thinks of matrix products like that, it's helpful to remember that matrices, unlike vectors, have two sets of bases: one for the domain and one for the range Thinking of applying a vector on to the right, we get that the transformation "unrotates" the vector, applies the original transformation in the original basis
- 为什么 1 不能被认为是质数？ - 知乎
谢邀。1原本是作为质数的，因为它本身满足质数的定义（1只可以被1和它本身整除）。1之所以被排除质数的范围，是因为我们有如下定理： （唯一分解定理）对于任意整数 m ，有且仅有一组质数对 (p_1,p_2,p_3,\cdots ,p_n) 和正整数对 (a_1,a_2,a_3,\cdots ,a_n) ，使得
- factorial - Why does 0! = 1? - Mathematics Stack Exchange
$\begingroup$ The theorem that $\binom{n}{k} = \frac{n!}{k!(n-k)!}$ already assumes $0!$ is defined to be $1$ Otherwise this would be restricted to $0 <k < n$ A reason that we do define $0!$ to be $1$ is so that we can cover those edge cases with the same formula, instead of having to treat them separately
- Why is $1$ not a prime number? - Mathematics Stack Exchange
actually 1 was considered a prime number until the beginning of 20th century Unique factorization was a driving force beneath its changing of status, since it's formulation is quickier if 1 is not considered a prime; but I think that group theory was the other force
- 2025年8月哪一款手机性价比高？全品牌、全价位手机推荐与选购指南（国补恢复版）
1、华为 作为国民品牌的华为，基本上是家喻户晓的，除了华为公司知名度高、实力雄厚之外，它的手机确实很值得称赞。 华为手机不论是是高端机还是低端机，在机子的做工、质量、系统、续航、性能等方面都是很用心的，曾经是国内手机销量第一的品牌
- 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。
- 2025年 8月 CPU天梯图（更新锐龙9 9950X3D） - 知乎
桌面端CPU综合性能天梯图，提供最新的CPU性能排名和对比信息，帮助用户了解不同型号的表现和选择适合自己的产品。
|