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  1. What does $QAQ^{-1}$ actually mean? - Mathematics Stack …

    Apr 28, 2020 · I'm self-learning Linear Algebra and have been trying to take a geometric approach to understand what matrices mean visually. I've noticed this matrix product pop up repeatedly …

  2. 知乎 - 知乎

    知乎是一个可信赖的问答社区,汇集了各行各业的亲历者、内行人和领域专家,为用户提供高质量的内容和交流机会。

  3. summation - Sum of 1 + 1/2 - Mathematics Stack Exchange

    How do I calculate this sum in terms of 'n'? I know this is a harmonic progression, but I can't find how to calculate the summation of it. Also, is it an expansion of any mathematical function? 1 ...

  4. 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。

  5. 1/8, 1/4, 1/2, 3/4,7/8英寸分别是多少厘米? - 知乎

    把1英寸分成8等分: 1/8 1/4 3/8 1/2 5/8 3/4 7/8 英寸。 This is an arithmetic sequence since there is a common difference between each term. In this case, adding 18 to the previous term in the …

  6. 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 …

  7. 空调一级能效和三级能效开10小时,能差多少电费? - 知乎

    空调制冷+制热全年耗电量相差794-636=158度电 总结 海尔1.5匹空调,一级比三级年省电159度电 格力1.5匹空调,一级比三级年省电158度电 购买建议:空调使用寿命基本在5~10年,如果你 …

  8. Given a 95% confidence interval why are we using 1.96 and not 1.64?

    Oct 15, 2015 · Two reasons: 1) Students are in New Jersey. 2) the z z -value associated with 95% is z=1.96; this can be seen as part of the 1-2-3, 65-95-99 rule that tells you that values within …

  9. Mathematics Stack Exchange

    Q&A for people studying math at any level and professionals in related fields

  10. 2025年 7月 电脑配置推荐(配置单可以直接照抄) - 知乎

    2025年七月台式机电脑DIY配置推荐(这篇文章每月都会更新,可以收藏)