Jan 6, 2026 · 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，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。

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？

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。

知乎是一个中文互联网高质量问答社区和创作者聚集的原创内容平台，提供知识共享、互动交流和个人成长机会。

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?

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

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：

Aug 24, 2016 · Oh, it sounds like Ivm asking those questions rhetorically. I'm not. They are very subtle and difficult questions. Ponder them and think about them. Part of the problem is that we really …

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 …