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  1. Why is $1/i$ equal to $-i$? - Mathematics Stack Exchange

    May 11, 2015 · Why is 1/i 1 / i equal to −i i? Ask Question Asked 10 years, 8 months ago Modified 1 year ago Viewed 116k times

  2. factorial - Why does 0! = 1? - Mathematics Stack Exchange

    Possible Duplicate: Prove 0! = 1 0! = 1 from first principles Why does 0! = 1 0! = 1? All I know of factorial is that x! x! is equal to the product of all the numbers that come before it. The product of 0 and …

  3. If $A A^{-1} = I$, does that automatically imply $A^{-1} A = I$?

    Mar 30, 2020 · 1 Short Answer Yes AA -1 = A -1 A = I when the Det (A) ≠ ≠ 0 and A is a square matrix. Long Answer A matrix is basically a linear transformation applied to some space. For the sake of …

  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. What is the value of $1^i$? - Mathematics Stack Exchange

    Aug 30, 2010 · The formal moral of that example is that the value of 1i 1 i depends on the branch of the complex logarithm that you use to compute the power. You may already know that 1 =e0+2kiπ 1 = e …

  6. Formal proof for $(-1) \\times (-1) = 1$ - Mathematics Stack Exchange

    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?

  7. 为什么美国明明有1小时22分解决委内瑞拉的强大战力,却坐视乌克兰 …

    Jan 3, 2026 · 为什么美国明明有1小时22分解决委内瑞拉的强大战力,却坐视乌克兰的巨大牺牲、不愿帮助乌克兰取得胜利?

  8. 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。

  9. 2026年 1月 显卡天梯图(更新RTX 5090Dv2&RX 9060) - 知乎

    Jan 1, 2026 · 1080P/2K/4K分辨率,以RTX 5050为基准(25款主流游戏测试成绩取平均值) 数据来源于:TechPowerUp 桌面端显卡天梯图:

  10. 商务部表示为维护国家安全和利益,决定加强两用物项对日本出口管 …

    商务部公告2026年第1号关于加强两用物项对日本出口管制的公告根据《中华人民共和国出口管制法》等法律法规有关规定,为维护国家安全和利益、履行防扩散等国… 显示全部 关注者 5,177 被浏览