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fermatslibrary's profile
Fermat's Library
Fermat's Library
Fermat's Library
@fermatslibrary

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Fermat's Library

@fermatslibrary

A platform for illuminating academic papers. We publish an annotated paper every week. Our chrome extension for arXiv: https://fermatslibrary.com/librarian 

fermatslibrary.com
Joined September 2015

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    Fermat's Library‏ @fermatslibrary 16 Apr 2018
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    FUN FACT: In Algebra we commonly use the lowercase letters a, b, c for known quantities and x, y and z for unknown quantities. This notation was first introduced by René Descartes in "La Géométrie" published in 1637 as an appendix and proof-of-concept for a work on Philosophy🤔pic.twitter.com/nVfgGOZSZN

    6:08 AM - 16 Apr 2018
    • 897 Retweets
    • 2,600 Likes
    • Hang_Zhang Eliyahu Switzer Álvaro J. Castro Rivadeneira Twitty Mc Twittface Vinod Ananay Ritesh Ramiel.jpg 卐
    26 replies 897 retweets 2,600 likes
      1. New conversation
      2. Amine Ouazad‏ @amine_ouazad 16 Apr 2018
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        Replying to @fermatslibrary @BaldwinRE

        Completely inaccurate. https://www.ted.com/talks/terry_moore_why_is_x_the_unknown/up-next … the use of x in medieval manuscripts predates Descartes’ use by multiple centuries.

        2 replies 3 retweets 11 likes
      3. Steven Strogatz‏Verified account @stevenstrogatz 16 Apr 2018
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        Replying to @amine_ouazad @fermatslibrary @BaldwinRE

        I would be interested in learning what those specific medieval manuscripts are, if they exist. If Terry Moore has actual evidence, that would be really interesting. Are you aware of any?

        2 replies 0 retweets 2 likes
      4. 6 more replies
      1. New conversation
      2. 傲览千古‏ @lxg6226 16 Apr 2018
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        Replying to @fermatslibrary

        你说得很对。笛卡尔同学写了一本“几何学”,开创了“字母表的开头的小写字母是待定常量,字母表末端的小写字母代表未定变量。关键是,所有的小写字母,都是代数。”这种案例。

        1 reply 0 retweets 2 likes
      3. 傲览千古‏ @lxg6226 16 Apr 2018
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        Replying to @lxg6226 @fermatslibrary

        我们看了笛卡尔同学写的“几何学”,这本书在历史上之所以非常重要,今天各国的代数学和几何学的规范,都源自这本书。而且,后来他和费马同学还发现了平面座标几何学。在这种平面座标几何学中,座标轴常常是只画出一根,而不是像今天世界各国中学和大学中的数学和物理教科书,总是把平面座标轴画成两根。

        1 reply 1 retweet 2 likes
      4. 1 more reply
      1. mangledPixel‏ @mangledpixel 16 Apr 2018
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        Replying to @fermatslibrary

        and is therefore the origin of using 'x' to mean 'unknown' in other contexts, too (X-Files, Planet X, X-factor, etc.)

        0 replies 0 retweets 2 likes
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      1. New conversation
      2. Emmanuel C‽aiя‏ @BzhClair 16 Apr 2018
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        Replying to @fermatslibrary

        Looks like the solution of a quadratic function. The mathematical notation is more modern than the French. One discovers that during those Cartesian times, letter f was quite used , stayed as s in English became varied accents in French see mefme became même.

        1 reply 0 retweets 1 like
      3. Dag-Erling Smørgrav‏ @desdotdev 16 Apr 2018
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        Replying to @BzhClair @fermatslibrary

        That's “ſ”, not “f”. That's how a minuscule “s” was printed unless it was a) the second of a double “s”) or b) the final letter of a word. Hence the German “ß”, which started out as a ligature of “ſs”. https://en.wikipedia.org/wiki/Long_s 

        2 replies 0 retweets 1 like
      4. 1 more reply
      1. New conversation
      2. Mark Carmichael‏ @mark2carmichael 16 Apr 2018
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        Replying to @fermatslibrary

        so what?

        1 reply 0 retweets 0 likes
      3. Einar Ekeberg‏ @EkebergEinar 16 Apr 2018
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        Replying to @mark2carmichael @fermatslibrary

        Well, it’s a fun fact

        0 replies 0 retweets 2 likes
      4. End of conversation
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