explain xkcd - User contributions [en]

Talk:2606: Weird Unicode Math Symbols

2022-04-14T05:30:14Z

141.101.76.221:

Apparently, nobody knows what U+237C ⍼ means (https://ionathan.ch/2022/04/09/angzarr.html)
: For me it looks very like as designation of where electrical cable is burrowed. It should come with numbers near angle hands designating depth and offset from sign. But it just a guess, of course [[Special:Contributions/141.101.76.221|141.101.76.221]] 05:30, 14 April 2022 (UTC)

Can someone add a column where we try to crowdsource a description for the "mathematical use of symbol" ?

I'm curious what those symbols actually mean, and the unicode titles don't give that much information.

I do not doubt that have enough math geeks on here to find the answer to most of then :-D

Thanks!
[[User:Flekkie|Flekkie]] ([[User talk:Flekkie|talk]]) 01:20, 14 April 2022 (UTC)

i agree w Flekkie's comment
[[User:Blue in real life|Blue in real life]] ([[User talk:Blue in real life|talk]]) 02:27, 14 April 2022 (UTC)

If you make edits, please don't immediately delete all of mine because you think yours are better. It shows you conflicting edits for a reason. Some explanations are nonsensical, like defining a smash product as the "result of dividing two product spaces." The smash product is specifically the quotient of the underlying spaces of two pointed spaces where points in the product spaces are identified if they contain either labeled point as an element. Other claims are simply mistaken. For instance, the ≝ symbol is used to introduce a definition, not to declare that the definition has been achieved in a proof. The claim that "A union on smash product appears to be one where the sets are nit isomorphic" is totally meaningless. The symbol ⩩ is not merely decorative but is intended as a supplemental math symbol like all the others. I couldn't track down its purpose. The APL symbol description somehow never bothers to mention APL. This is all very cursory, which is fine, but just please don't delete my work while doing it. [[Special:Contributions/172.70.130.5|172.70.130.5]] 04:15, 14 April 2022 (UTC)
:I'm done, page is yours. I'd been working on it for an hour and every time I tried to save, a new edit came in. I did my best to reconcile them but by the fifth I just saved a copy of what was there and pasted mine over. I immediately got to work on recovering what I had pasted over as indicated in the edit comment and like I said, I'm done. I've merged to the best of my ability and have no more interest in this page.
:--[[User:FrankHightower|FrankHightower]] ([[User talk:FrankHightower|talk]]) 04:37, 14 April 2022 (UTC)
::I'm very sorry if I was one of those who stepped on your edits. I was originally trying to fix brokenness in the table. ^^^^^ ≫ ^ is the symbol for preferring many small edits over not saving your work often in a batch-mode collaborative editing environment. [[Special:Contributions/172.70.207.8|172.70.207.8]] 04:55, 14 April 2022 (UTC)

I wish we had as much research on ⧍ and ⩩ as we have for ⍼. [[Special:Contributions/172.70.207.8|172.70.207.8]] 05:16, 14 April 2022 (UTC)

2605: Taylor Series

2022-04-13T05:20:18Z

141.101.76.221: /* Explanation */

{{comic
| number = 2605
| date = April 11, 2022
| title = Taylor Series
| image = taylor_series.png
| titletext = The Taylor series should have been canceled after the first term.
}}

==Explanation==
{{incomplete|Created by THE MACLAURIN SERIES EVALUATED AT X PLUS EPSILON - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

In mathematics, the {{w|Taylor series}} of a function is an infinite sum of terms that are expressed as the function's {{w|Derivative|derivatives}} multiplied with a power of a distance and a coefficient, giving a polynomial approximation of the function at a specific point. Their expressions, usually referred to as "expansions," continue (except for - possibly piecewise - polynomial functions; for those the Taylor series would finally result in the originating polynomial function) without end. Taylor series are useful for approximating smooth functions within the neighborhood of a point. They are also useful for deriving numerical approximations of {{w|Irrational number|irrational}} values, {{w|Machin-like formula|such as π}}, as well as {{w|Symbolic integration|symbolic}} forms to make them easier to integrate or otherwise manipulate with calculus.[https://www.mathsisfun.com/algebra/taylor-series.html] However, because they involve difficult calculus operations, and can be annoyingly tedious to {{w|Numerical analysis|calculate by hand}}, they are often not loved by math students{{citation needed}}.

[[Miss Lenhart]] appears to be teaching a class about how to use a Taylor series. She has explained what one is, and how it is used. She presumes her students want to keep learning about the series, in that they, "wish it would never end." She then says "Good news!" because the Taylor series does not end, each term being smaller than the last (in the vicinity of the point) as the exponent of the distance increases by one. The cartoon's humor is based on contrasting the idea of wishing the series will never end, which is ordinarily expressed regarding long-running sequences of enjoyable events, with the infinite nature of the Taylor series, which is probably not appreciated by her students struggling to understand why the sums {{w|Convergent series|converge}} to their resulting value.

The title text is a reference to the common practice among physicists and engineers of abbreviating the Taylor series to only the first few terms, typically one or two, in order to simplify the mathematics of their models. The title text is also a pun on the use of the word "series" to refer to a television program. It symbolizes the terms of the mathematical series as a {{w|metaphor}} with a television season, suggesting that only the first term is useful. It makes fun of the common sentiment against bad {{w|screenwriting}} of a series by saying that, "The series should have been cancelled after the first season," replacing "season" with "term." It should be noted that there do indeed exist functions for which the Taylor series has effectively only one term -- specifically, functions with a degree of zero, or where y is a constant value. All of the derivatives of these functions are zero, and thus the Taylor series is effectively a single term -- just the value itself.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

:[Miss Lenhart pointing a stick at a whiteboard, which has some scribbled text written on it and one line is circled.]
:Miss Lenhart: At this point, you're probably thinking, "I love this equation and wish it would never end!"
:Miss Lenhart: Well, good news!

:[Caption below the panel:]
:Taylor series expansion is the worst.

{{comic discussion}}

[[Category:Comics featuring Miss Lenhart]]
[[Category:Math]]

Talk:2591: Qua

2022-04-01T08:51:35Z

141.101.76.221: Added to disucssion about the different meanings of "qua" in the strip vs title text

As i've never seen anyone use this, we can safely assume that exterminating these people would not affect the world one bit [[Special:Contributions/162.158.191.131|162.158.191.131]] 10:39, 10 March 2022 (UTC)

If Megan's not careful, this pattern can quickly spiral to infinity: "Nice use of qua qua qua ''qua'' qua qua qua." "Nice use of qua qua qua qua qua qua qua ''qua'' qua qua qua qua qua qua qua." "Nice use of..." --mezimm [[Special:Contributions/172.70.178.93|172.70.178.93]] 16:37, 9 March 2022 (UTC)
:Or perhaps "Nice use of 'Nice use of ... '" although new forms of quote mark would need to be invented. --[[User:192·168·0·1|192·168·0·1]] ([[User talk:192·168·0·1|talk]]) 19:11, 9 March 2022 (UTC)
::From what I've seen, you just alternate between " and '. [[Special:Contributions/172.70.126.65|172.70.126.65]] 23:45, 9 March 2022 (UTC)
:Hey, [[244|no recursing]]. [[User:Ruffy314|Ruffy314]] ([[User talk:Ruffy314|talk]]) 21:46, 9 March 2022 (UTC)
'''qua qua qua qua qua qua qua qua qua qua qua qua qua qua qua qua qua qua qua qua qua qua qua qua''' [[User:New editor|New editor]] ([[User talk:New editor|talk]]) 20:37, 9 March 2022 (UTC)
:eh, close enough.[[User:Lettherebedarklight|youtube.com/watch?v=miLcaqq2Zpk]] ([[User talk:Lettherebedarklight|talk]]) 12:55, 10 March 2022 (UTC)

I feel like there should be a duck somewhere. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 21:05, 9 March 2022 (UTC)
Buffalo everywhere are concerned.

Maybe one could note that the two uses of "qua" are different: While in the meaning of "as"/"in capacity of", qua is a preposition, it is a relative pronoun in the Latin expression "sine qua non".
So, actually, the explanation of the title text given so far is slightly incorrect: The correct use of "qua" (as a preposition) is NOT essential to the correct use of "sine qua non" (where we use only the Latin relative pronoun). Instead, "qua" is essential to build the complex expression "sine qua non qua sine qua non", where the middle qua is indeed the preposition!
I also feel that Randall is making fun of "pretentious" people by demonstrating how quickly their talk turns into something like "blablabla" [[Special:Contributions/172.70.246.153|172.70.246.153]] 21:51, 9 March 2022 (UTC)

:But the explanation of the title text is not claiming that it is specifically as a proposition that “qua” is essential, is it?
:[[User:While False|While False]] ([[User talk:While False|talk]]) 04:31, 10 March 2022 (UTC)

:: Well, basically, you're right. But to clarify it better, you would at least have to point out that the title text is talking of two different "qua"s then, BOTH the preposition and the relative pronoun. And in order to use them correctly, you ought to differentiate between the both, i.m.h.o. [[Special:Contributions/162.158.90.171|162.158.90.171]] 07:38, 10 March 2022 (UTC)

:::I agree with you.

:This is a distinction without a difference. The Latin "qua" that we call an adverb is directly derived from "qua" the pronoun, ablative feminine form of "qui" ("which"). In fact, the simple ablative use of the pronoun completely covers the meaning of the adverb ("as", "by which", "as which" etc.). Calling some uses of "qua" adverbial, rather than simple ablative use of a feminine pronoun, is something modern linguists do to facilitate understanding of "qua" when not preceded by prepositions; it is not, I suspect, a distinction the Latin speakers of antiquity would recognise.

:::[[User:While False|While False]] ([[User talk:While False|talk]]) 08:22, 10 March 2022 (UTC)

Even after reading the comic, title text & the explainxkcd.com description, I am still confused. I've never heard of that word/phrase.

:Agreed, I feel that the explanation qua it stands leaves me almost qua confused qua I was before coming here and reading it. If qua roughly means “as” or “for the purpose of” then would someone please explain why this not an example of someone using sine qua non: “I could have left work after the accident if I wanted, but decided sine, bore the pain, and stayed.” I don’t get it.[[Special:Contributions/172.70.131.214|172.70.131.214]] 06:47, 10 March 2022 (UTC)

:Yeah, it's only really familiar to people who speak Higher Academic. I think at least three nines of all uses of the word "qua" in English-language writing are in the phrase "sine qua non", which is itself too prolix to really qualify as common. The main thing that saves "sine qua non" from being jargon, is that it's not in any way discipline-specific. It's as likely to show up in a formal academic paper related to algebraic topology, as it is to show up in a formal academic paper related to medieval literature. This puts it into the same general category as e.g. "albeit", "je ne sais quoi", or "prolix". As for uses of the word "qua" outside the context of the phrase "sine qua non", I believe this may be the first I've ever encountered, so it's difficult to generalize. --Jonadab (not logged in).
::Hey, I actually use "albeit" all the time! (British English? Possibly even regional dialect. But I also use "whilst" a lot, and know that people like to assume that I mean "while", never mind the occasional confusion between the usage as meaning "during" or the one that means "until" ({{wiktionary|while#Conjunction|c.f. usages 3 and 4!}}) Not that I've used a "naked ''qua''" at all, that I can recall, only really used ''je ne sais quoi'' when speaking yer actual French, whilst ''prolix'' is unknown to me and out of context I'd have thought it a medical term... ;)[[Special:Contributions/172.70.90.173|172.70.90.173]] 21:18, 15 March 2022 (UTC)

On this you are not alone.

If you say "Qua Qua Qua Qua" really fast, it kind of sounds like you are saying "quack quack quack". Thus Megan would sound like she is saying "Nice use of quack quack quack quack..." [[Special:Contributions/162.158.107.230|162.158.107.230]] 00:56, 10 March 2022 (UTC)

: “Qua qua qua” is how in Italian you write the duck sound. [[User:Vdm|Vdm]] ([[User talk:Vdm|talk]]) 21:23, 11 March 2022 (UTC)

This comic is most likely inspired by this week's Sunday puzzle on NPR, which asks for an English word that starts with the "kw" sound but doesn't contain Q,U,K, or W. See https://www.npr.org/2022/03/06/1084744124/sunday-puzzle-may-the-odds-be-in-your-favor
:Well, apart from the u...[[Special:Contributions/172.69.79.153|172.69.79.153]] 17:19, 10 March 2022 (UTC)
:My answer to the puzzle is "choir" [[User:Rtanenbaum|Rtanenbaum]] ([[User talk:Rtanenbaum|talk]]) 20:20, 10 March 2022 (UTC)

Quamvis sint sub aqua sub aqua maledicere temptant. Sebastian --[[Special:Contributions/172.70.251.88|172.70.251.88]] 06:22, 10 March 2022 (UTC)

Randall is not using qua qua qua qua qua qua qua qua qua qua qua qua qua qua qua, he's using it to sound funny and play with words. [[User:Fabian42|Fabian42]] ([[User talk:Fabian42|talk]]) 07:24, 10 March 2022 (UTC)

:I think Randall is just trying to sound pretentious coûte que coûte ;-P --[[User:IByte|IByte]] ([[User talk:IByte|talk]]) 10:33, 10 March 2022 (UTC)

No reference here to Waiting for Godot?

:People only reference Waiting for Godot in order to sound pretentious. Nobody has ever actually read it.

::Because it's a play? … You usually don't read a play. … Especially one … with so many … pauses.
::(Well, at least five people will then read the play. Whosoever play Estragon, Vladimir, Pozzo, Lucky and the boy(s). Nobody who plays Godot.)
::You can always tell people you read ''Waiting For Godot'' in the original French, if you really want to sound pretentious. … Or French. [[Special:Contributions/172.70.90.173|172.70.90.173]] 21:18, 15 March 2022 (UTC)

I am anxiously awaiting the day when I come to explainxkcd and the content for that day's comic is just "...look, I don't know man"
:Yes. and I am waiting for someone to answer, "...it's just funnier that way." [[User:Rtanenbaum|Rtanenbaum]] ([[User talk:Rtanenbaum|talk]]) 20:20, 10 March 2022 (UTC)

Perhaps it would help to explain to use angle brackets:
- Cueball: <qua> qua <qua> ''("qua-word" _used for_ "qua-meaning"), but also ("any word/expression" _used for_ "its own meaning") with the two outer "qua" = abbreviation of "aliqua" in the meaning of "something"''
- Megan: <<qua> qua <qua>> qua <<qua> qua <qua>> ''("qua qua qua"-wording _used for_ "qua qua qua"-meaning)''
- Title Text: <Qua> qua <qua> is the <sine qua non> of <<sine qua non> qua <sine qua non>> ''"qua qua qua"-meaning/construct is the _indispensable essence_ of "sine qua non"-wording _used for_ "sine-qua-non"-meaning''
Sebastian --[[Special:Contributions/172.70.242.207|172.70.242.207]] 06:02, 11 March 2022 (UTC)

I have trouble reading the word <code>qua</code>, my brain seems to automatically reorient it, so I can comfortably read <code>end</code>. --[[Special:Contributions/162.158.92.193|162.158.92.193]] 17:44, 12 March 2022 (UTC)

I am guessing that "Badger badger Badger badger badger badger Badger badger" is just as valid as "Buffalo buffalo Buffalo buffalo buffalo buffalo Buffalo buffalo"? [[User:These Are Not The Comments You Are Looking For|These Are Not The Comments You Are Looking For]] ([[User talk:These Are Not The Comments You Are Looking For|talk]]) 00:54, 14 March 2022 (UTC)
: No, because the plural of "badger" is "badgers", not "badger". Also "Badger" isn't a well-known city, if it is indeed a place. [[Special:Contributions/172.70.130.153|172.70.130.153]] 05:34, 15 March 2022 (UTC)
::If we are going to accept the use of "buffalo" as the plural form of buffalo [https://www.wordhippo.com/what-is/the-plural-of/buffalo.html when it is actually "buffalos/buffaloes"], then "badger" as a plural should also be valid. [https://en.wikipedia.org/wiki/Badger,_Alaska Badger, Alaska] has the largest population of the [https://en.wikipedia.org/wiki/Badger_(disambiguation) seven places with that exact name](~19,000). However, the popularity of the location doesn't matter to the validity of the sentence, as long as it exists. [[User:These Are Not The Comments You Are Looking For|These Are Not The Comments You Are Looking For]] ([[User talk:These Are Not The Comments You Are Looking For|talk]]) 04:59, 16 March 2022 (UTC)
:::"{{wiktionary|buffalo#Noun|buffalo (plural buffaloes or buffalos or buffalo)}}" vs "{{wiktionary|badger#Noun|badger (plural badgers)}}" [[Special:Contributions/172.70.86.44|172.70.86.44]] 12:10, 16 March 2022 (UTC)
::::OK, I admit that I stopped after I found a link that I thought supported my argument. I resubmit it as: ''Badger badgers Badger badgers badger badger Badger badgers.'' [[User:These Are Not The Comments You Are Looking For|These Are Not The Comments You Are Looking For]] ([[User talk:These Are Not The Comments You Are Looking For|talk]]) 20:24, 21 March 2022 (UTC)
:::::Can mushroom mushroom? --[[User:192·168·0·1|192·168·0·1]] ([[User talk:192·168·0·1|talk]]) 23:42, 23 March 2022 (UTC)
::::::Snake snake.... Snake... [[Special:Contributions/172.70.162.147|172.70.162.147]] 01:48, 24 March 2022 (UTC)

The second, third, and fourth sentences still need a lot of work, folks. [[Special:Contributions/172.70.211.72|172.70.211.72]] 09:00, 21 March 2022 (UTC)