Timeline for Explanation why $x,y,z$ are always variables
Current License: CC BY-SA 2.5
21 events
| when toggle format | what | by | license | comment | |
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| Apr 13, 2017 at 12:58 | history | edited | CommunityBot |
replaced http://mathoverflow.net/ with https://mathoverflow.net/
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| Dec 7, 2012 at 18:55 | comment | added | Alexander Chervov | Similar question: mathoverflow.net/questions/104031/… | |
| Nov 30, 2011 at 13:55 | answer | added | Marc van Leeuwen | timeline score: 14 | |
| Sep 22, 2010 at 12:03 | vote | accept | Roland Bacher | ||
| Jul 4, 2010 at 21:34 | vote | accept | Roland Bacher | ||
| Jul 4, 2010 at 21:40 | |||||
| Jul 3, 2010 at 14:07 | answer | added | Mariano Suárez-Álvarez | timeline score: 29 | |
| Jul 2, 2010 at 22:14 | comment | added | Anton Geraschenko | It's a bit late to post this link, but I'll do so anyway. Meta thread: tea.mathoverflow.net/discussion/486/x-y-z | |
| Jul 2, 2010 at 17:58 | history | reopened |
Kevin H. Lin Mariano Suárez-Álvarez Joel David Hamkins François G. Dorais |
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| Jul 2, 2010 at 17:49 | comment | added | Joel David Hamkins | Mariano, when the question is reopened, could you kindly post your comment as an answer? | |
| Jul 2, 2010 at 16:47 | comment | added | Mariano Suárez-Álvarez | (continued) earlier than the book by years. It is very, very interesting to read through the description Cajori makes of the many, many other alternatives to the notation of quantities, and as one proceeds along the almost 1000 pages of the two volume book, one can very much appreciate how precious are the notations we so much take for granted! | |
| Jul 2, 2010 at 16:44 | comment | added | Mariano Suárez-Álvarez | You'll find details on this point in Cajori's History of mathematical notations, ¶340. He credits Descartes in his La Géometrie for the introduction of $x$, $y$ and $z$ (and more generally, usefully and interestingly, for the use of the first letters of the alphabet for known quantities and the last letters for the unknown quantities) He notes that Descartes used the notation considerably earlier: the book was published in 1637, yet in 1629 he was already using $x$ as an unknown (although in the same place $y$ is a known quantity...); also, he used the notation in manuscripts dated | |
| Jul 2, 2010 at 14:52 | comment | added | Wadim Zudilin | Scott, aren't there holidays? (from maths) $\ddot{\smile}$ | |
| Jul 2, 2010 at 14:44 | comment | added | S. Carnahan♦ | I'm afraid the concentration of non-mathematics questions is getting out of hand here, so I'm closing this one. Incidentally, the OED also mentions that Descartes started with $z$ and progressed backwards. | |
| Jul 2, 2010 at 14:40 | comment | added | Wadim Zudilin | @Roland: I'll check your newer convention on my most experienced students. :-) I've tried to dig something about your legend but it looks coming from nowhere... I am definitely confused as I heard it in exactly the same from many years ago. | |
| Jul 2, 2010 at 14:36 | history | closed | S. Carnahan♦ | off topic | |
| Jul 2, 2010 at 14:27 | comment | added | PersonX | The Oxford English Dictionary credits Descartes with the introduction (in their entry for "X"), but makes no mention of the issue with the printers. The OED also says "no evidence in support of the hypothesis that x is derived ultimately from the mediæval transliteration" from Arabic. | |
| Jul 2, 2010 at 14:23 | comment | added | Roland Bacher | Wadim, thank you for the link which gives a more likely explanation. By the way, I find it amazing how useful notational conventions are. Illustration: A function $\epsilon$ is continuous at $f$ if for arbitrarily small positive $N$ there exists a positive $x$ such that $\vert\epsilon(f)-\epsilon(A)\vert<N$ if $\vert A-f\vert\leq x$. (Writing such an example makes me empathic to students.) | |
| Jul 2, 2010 at 14:05 | comment | added | Wadim Zudilin | As I learned your story from high school, I am pretty sure it's a legend. From wiki (standard convention): en.wikipedia.org/wiki/Variable_%28mathematics%29 | |
| Jul 2, 2010 at 14:05 | comment | added | Roland Bacher | Wadim, what is CW? | |
| Jul 2, 2010 at 14:00 | comment | added | Wadim Zudilin | Roland, this is definitely CW! | |
| Jul 2, 2010 at 13:37 | history | asked | Roland Bacher | CC BY-SA 2.5 |