explain xkcd - User contributions [en]

2966: Exam Numbers

2024-08-01T08:21:01Z

172.68.186.90: /* Explanation */

{{comic
| number = 2966
| date = July 31, 2024
| title = Exam Numbers
| image = exam_numbers_2x.png
| imagesize = 553x400px
| noexpand = true
| titletext = Calligraphy exam: Write down the number 37, spelled out, nicely.
}}

==Explanation==
{{incomplete|Created by 10 MORE THAN AVERAGE MATH TEACHERS - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

The comic depicts various similarly formatted examination questions that might appear on test papers at various points in a student's potential academic career. While they all share a similar feel, they are asking for different things, some of which might be considered more serious and examinable proofs of study than others. The joke is that the first and last questions are the same, but have very different interpretations based on the context.
{| class="wikitable"
|+ Exam numbers
! Exam level !! Question !! Answer
|-
| {{w|Kindergarten}} math || Write down the biggest number you can think of || At a kindergarten-level education, it is assumed that an individual might write down a relatively small number like 300, depending upon whether they have encountered the concept of hundreds. It might also be interpreted as "what's the highest number that you (think you) can count up to". Given the nature of a child's exuberant glee at learning about ''really'' big (but otherwise normal) numbers, they may even try an answer something like "a million billion squillion gazillion". It is not certain what criteria would be used to mark this question correct or otherwise, it may actually by a stealth question in child psychology or a question that everybody "gets right" so long as they answer it.
|-
| Pre-{{w|algebra}} || Write down the value of x if x=3x-8 ||

''3x'' refers to the multiplication of 3 and the originally unknown number ''x'', as a convenient shorthand.

By subtracting ''3x'' from both sides, ''-2x = -8''. Divide both sides by -2 to find ''x''=4. Alternately, subtract ''x'' from both sides to give ''0 = 2x - 8'', and as taking 8 from two ''x''s makes it zero, one ''x'' is half that

(Verify by plugging ''x''=4 into the original equation. '''4''' = (3*'''4''') - 8 -> '''4''' = 12 - 8 -> '''4''' = 4.)
|-
| {{w|Calculus}} || Write down the value of ∫0π x sin2 x dx || The integral of the expression is ''((x-sin(2*x))*2*x-cos(2*x))/8 + C''. Plugging in values for ''x'' gives the result as π2/4 = 2.4674...

If one assumes sin2 is an {{w|iterated function}} instead of a square, one instead gets π2{{w|Struve function|H0(1)}}/2 = 2.8062...
|-
| PhD {{w|Cosmology}} || Write down the Hubble constant to within 1% || The Hubble constant is a component of {{w|Hubble%27s_law|Hubble's law}}, which describes the relationship between the distance between galaxies and their speed of separation. Its exact value is not known to this level of accuracy; it is about 2.3×10-18 Hz. Different methods of measuring it have come up with significantly different values, and resolving this difference (the {{w|Hubble's_law#Hubble_tension|Hubble tension}}) is one of the great challenges of modern cosmology. This question might have a different acceptable answer in the future, depending upon further developments in cosmology (although the 'constant' itself changes over time).
|-
| {{w|Game Theory}} || Write down 10 more than the average of the class's answers || Game Theory studies "games" in which two or more participants' take actions that will succeed or fail based on other participants' decisions. In this case, all students' answers will be averaged, and the best answer will be 10 more than that average. If a student knew what everyone else was thinking, this would incentivise them to answer 10 more than the consensus (taking into account their own forthcoming answer), which would not necessarily be the largest number written down. For instance, if the answers end up being 30, 40, 50, 60, and 70, the most correct of these answers is 60.

In reality, most game theory exams test your understanding of game theory as an academic subject, not your ability to win games. (A type of class where actual results may result in better grades is a business negotiation class where the results of practice negotiations can determine one's grade on the assignment.)

Something similar to this question is found in the title text of [[2385: Final Exam]].
|-
| Postgraduate Math || Write down the biggest number you can think of || This question echoes the very first example, but would be expected to be answered very differently (unlike a revisiting of most of the others).
Postgraduate math students can probably think of ''very'' large numbers. While the "best" answer could be "infinity" since, depending on your definition of the word "number", infinity may be the largest possible number that you will have encountered, students familiar with the field of [https://googology.fandom.com/wiki/Googology#History Googology] may consider infinity a concept rather than a number, and might give an answer such as Rayo's Number, which was the winning entry in the [https://googology.fandom.com/wiki/Big_Number_Duel Big Number Duel].

This might heavily depend upon the branch of mathematics you are studying, however, as named (finite) numbers or ones with specific and useful notations might satisfy some questioning contexts, whilst the existence of a whole further set of trans-finite numbers (i.e. increasingly large types of "infinity") would be important considerations in others. For those associated with more computational mathematics, any infinity be {{w|NaN|Not a Number}}, and their answer might instead be the ceiling of some binary representation (typically ''28n-1'' for some value of ''n''), the largest value reliably storable in byte form (e.g. a {{w|Integer (computer science)|double quadword}}).

As with the kindergarten question, there may be no previously anticipated "correct" answer. It could be another "correct just so long as you answer it" (or perhaps "sensibly" so) or the mark goes only to those giving the greatest number across all submissions.
|-
| {{w|Calligraphy}} (title text) || Write down the number 37, spelled out (as "thirty-seven" or "thirty seven"), nicely || Calligraphy is the art of artistic writing. The title text expands the joke outside the realm of math and points out that since calligraphy does not require any math skills, the only way a calligraphy exam would even mention numbers is if one had to write them out in such a way as to showcase their calligraphic skill. {{w|37}} is a number that some people believe [http://thirty-seven.org mysteriously appears more often than it should]; this was a subject of a [https://www.youtube.com/watch?v=d6iQrh2TK98 recent Veritasium video].
|}

This final exam question, un-numbered and therefore possibly the ''only'' question upon the whole of each final paper, in some ways (for some instances) echoes the question "What is your name?" that Randall will be aware was the sole question given to Discworld's {{w|List of Discworld characters#Victor Tugelbend|Victor Tugelbend}} in an attempt to ensure he comprehensively passed (or utterly failed) his final student-wizard's exam, after many prior times of deliberately not-quite-passing.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[6 different math test questions.]

:[The first panel:]
:Kindergarten math final exam
:Q. Write down the biggest number you can think of
:A. [empty box]

:[The second panel:]
:Pre-algebra final exam
:Q. Write down the value of x if x=3x-8
:A. [empty box]

:[The third panel:]
:Calculus final exam
:Q. Write down the value of [integral sign, from 0 to pi] x sin^2 x dx
:A. [empty box]

:[The fourth panel:]
:PhD cosmology final exam
:Q. Write down the Hubble constant to within 1%
:A. [empty box]

:[The fifth panel:]
:Game theory final exam
:Q. Write down 10 more than the average of the class's answers
:A. [empty box]

:[The sixth panel:]
:Postgraduate math final exam
:Q. Write down the biggest number you can think of
:A. [empty box]

{{comic discussion}}

[[Category:Math]]
[[Category:Cosmology]]

Talk:2965: Chili Tornado Quake

2024-07-30T13:11:23Z

172.68.186.90:

for some reason I always feel nervous providing an initial transcript like I'm gonna do the format wrong but nah this transcript is pretty simple, would be hard to get it very wrong - [[User:Vaedez|Vaedez]] ([[User talk:Vaedez|talk]]) 04:02, 30 July 2024 (UTC)
:No need to worry cause it can always be changed. I have tweaked the transcript a bit. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 09:06, 30 July 2024 (UTC)

wait--is the titletext missing a "due"? - [[User:Vaedez|Vaedez]] ([[User talk:Vaedez|talk]]) 04:04, 30 July 2024 (UTC)
:I think so, yeah. First time I've seen Randall make a mistake in the alt text. [[Special:Contributions/162.158.137.212|162.158.137.212]] 04:33, 30 July 2024 (UTC)
::I have seen this several times, and sometimes he fixed it later. I have added this to a trivia section. If it is changed, it should still be mentioned there, but of course updated with the original mistake instead. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 09:06, 30 July 2024 (UTC)

Funnily enough, an earthquake large enough to shake the house occurred near me today! No chili peppers and definitely no tornadoes nearby, (un)fortunately. [[Special:Contributions/162.158.91.92|162.158.91.92]] 04:02, 30 July 2024 (UTC)

Wonder how the scales combine. Given that Richter and Fujita are both single digit numbers (well, Richter can go above 10, but normally only when Roland Emmerich is directing), they would be pretty meaningless in an additive scale, so I would assume multiplicative. If so, the amount of damage to the building suggests relatively mild peppers.[[User:RegularSizedGuy|RegularSizedGuy]] ([[User talk:RegularSizedGuy|talk]]) 04:11, 30 July 2024 (UTC)
:what if it's like a geometric mean or smth? that feels like it makes more sense than additive and it would also allow the average pepper involved in the incident to be ''higher'' than the 55k listed - [[User:Vaedez|Vaedez]] ([[User talk:Vaedez|talk]]) 04:19, 30 July 2024 (UTC)
::I believe the only method that makes sense is multiplying. Since spicy can go to 0, then 2000-3000 is probably still pretty strong for most people? Anyway, it may have been a smaller earthquake and not that big a tornado, maybe 3 and 6 then it alt least get above 3000. I have added these considerations to the explanation. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 09:06, 30 July 2024 (UTC)
::3000 is a low-end jalapeno, even a serrano is about 10k. Habanero is a couple of 100k. Would it be complete scientific abomination to take Fujita/Richter as additive and then multiply the result by scoville? [[Special:Contributions/172.69.43.167|172.69.43.167]] 13:00, 30 July 2024 (UTC)

I could have sworn Randall already made this joke... Maybe I'm thinking of [[1531]]. [[Special:Contributions/172.69.60.147|172.69.60.147]] 05:43, 30 July 2024 (UTC)

on the current state of the trivia section, i'm pretty sure we're not supposed to have opaque links that say "here" and have some comic they go to and that the structure of the sentence should be more like "in [comic x] randal also...", but i'm too tired to phrase it out rn and not entirely sure of this either - [[User:Vaedez|Vaedez]] ([[User talk:Vaedez|talk]]) 08:19, 30 July 2024 (UTC)
:I agree and also we usually do not make a trivia section to link to relevant comics so I moved it into the explanation. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 09:06, 30 July 2024 (UTC)

Is it relevant that Twisters just came out a couple weeks ago? [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 12:37, 30 July 2024 (UTC)

Though I agree that a multiplicative compound unit is most likely (unlike the additive Erdős–Bacon one, and further variations), it's worth noting that you can have F0 tornados, zero (as well as negative) in the Richter scale and/or 0 Scoville peppers (though the latter less likely, here). If either of the first two are counted as zero, they stil ''exist'', but means that any (finite) values attributed to the remaining measure would never produce a combined unit that is non-zero. So you probably have to lower-limit the Tornado measurement and ensure the Earthquake one is >0 to back-calculate any sensible Pepper value. If done as per the EB method, though, it just means that the source Scoville number is pretty much the whole contributor to the resulting sum (even if itçs an F5 with a 10 on the Ricbter scale, it's just 15 less than the merged value). Geptetic meandrians, aside, there are few other 'logical' functions between these three source values and the combo-evaluation, but many that might stretch plausibility. [[Special:Contributions/172.68.186.90|172.68.186.90]] 13:11, 30 July 2024 (UTC)

2964: Olympic Sports

2024-07-29T08:58:43Z

172.68.186.90: /* Explanation */

{{comic
| number = 2964
| date = July 26, 2024
| title = Olympic Sports
| image = olympic_sports_2x.png
| imagesize = 553x328px
| noexpand = true
| titletext = Thankfully for everyone involved, the Winter Olympics officials spotted me and managed to stop me before I got to the ski jump.
}}

==Explanation==
{{incomplete|Created by A VERY CONCERNED OLYMPIC OFFICIAL - Provide an explanation of each sport for the convenience of those unfamiliar with some or all listed sports. Do NOT delete this tag too soon.}}

This comic was officially published on the day of the opening ceremony of the {{w|2024 Summer Olympics|2024 Paris (Summer) Olympics}}, though it actually appeared early the following day.

In this comic, [[Randall]], who has no athletic training, imagines himself participating in various Olympic events, with his degrees of failure measured in terms of their humor potential.

{| class="wikitable"
|+ Olympic sports ranked by how funny it would be if a regular person competed
! How funny !! Sport !! Reason !! Depiction
|-
|rowspan=5| Not that funny || {{w|Rowing}} - One or more people row a boat to a destination.|| The person would struggle to row effectively, falling out of cadence and fouling the oars of the other rowers in their boat. However, if Randall competed in the single sculls, such coordination would not be an issue, and he would likely just be much slower than the other competitors. ||
|-
| {{w|Fencing}} - Two contestants attempt to land hits on each other with a long fencing weapon.|| They might fail to land any hits, but it wouldn't be overly humorous. ||
|-
| {{w|Weightlifting}} || They might just fail to lift the weights. ||
|-
| {{w|Golf}} - Contestants attempt to hit, with golf clubs, a golf ball into one or more holes in as small a number of hits as possible.|| They would likely miss the ball or hit poorly. || The illustration depicts Randall missing the hole at very close range.
|-
| {{w|Archery}} - Using a bow and arrow, contestants attempt to hit a target with as much accuracy as possible.|| Arrows might miss the target, but it's not particularly amusing. || Randall misses all his shots on the target.
|-
|rowspan=5| Pretty funny || {{w|Swimming}} - Contestants swim to a destination or complete lengths as fast as possible.|| They might struggle to stay afloat or [https://en.wikipedia.org/wiki/Eric_Moussambani swim awkwardly]. They are also likely to have a markedly different physique to the other competitors. ||
|-
| {{w|Long jump}} - Contestants, with a running start, attempt to jump as far as possible.|| They would likely make a very short jump. ||
|-
| {{w|Pole vault}} - Using a bendable pole, contestants attempt to propel (vault) themselves over a bar.|| They would miss the plant and end up dropping the pole and running under the bar. ||
|-
| {{w|Diving}} - Contestants attempt to fulfil multiple criteria while diving into water.|| Awkward or painful-looking dives could ensue. ||
|-
| {{w|Hurdles}} - Contestants run on a track with hurdles positioned at various places.|| They might trip and fall over the hurdles. || Randall repeatedly and painfully runs into the hurdles, unable to jump over any of them. He appears to be holding a hand on his head, possibly covering his eyes or due to having hurt his head.
|-
|rowspan=5| Incredibly funny || {{w|Figure skating}} || They might slip and fall continually on the ice. ||
|-
| {{w|Horizontal bar}} - A horizontal bar is used to perform gymnastics.|| They might fail to perform any flips or fall off the bar. ||
|-
| {{w|Equestrian sports}} - Various activities involving the use of horses.|| They might struggle to control the horse or fall off. || Randall is completely unable to control his horse. He is in the process of falling off and is flailing his arms.
|-
| {{w|Freestyle BMX}} - Contestants ride BMX bikes and perform various tricks, and are then judged by trick quality.|| They might crash or fail to perform tricks. ||
|-
| {{w|Pommel horse}} - Using a gymnastic device somewhat similar to a horse, gymnasts perform various tricks.|| They might awkwardly flop around or fall off. || Randall is attempting to perform a routine but clearly is not very graceful, balanced or typically dynamic, as made apparent by the rather basic agitrons surrounding him.
|}

The title text may be a reference to ski jumper {{w|Vinko Bogataj}}, whose spectacular crash at a (non-Olympic) ski flying event in 1970 in Oberstdorf, (then) West Germany became emblematic of the expression "the agony of defeat" in the opening narration of the popular US television program "{{w|Wide World of Sports (American TV program)|Wide World of Sports}}". Alternatively the reference may be to {{w|Eddie the Eagle}}, whose poor performance at the {{w|1988 Winter Olympics}} led to the introduction of the top 50 or 30% qualifying rule.

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

:[Header above three panels:]
:Olympic Sports ranked by how funny it would be if I, a regular person without athletic training, snuck onto the team to compete:
:[Three panels are shown with a header, a bullet list with five listed sports in each, and one or two depictions of sports.]

:Not that funny
:Rowing
:Fencing
:Weightlifting
:Golf
:Archery
:[Cueball putts a ball with a golf club and misses the hole.]
:[Cueball is aiming with a bow. Three arrows are on the ground at various distances from the target.]

:Pretty funny
:Swimming
:Long jump
:Pole vault
:Diving
:Hurdles
:[Cueball runs stomach-first into a hurdle, while holding a hand on his head. Another hurdle behind him has fallen down.]
:Cueball: [Bonk] Ow! [Bonk] Ow!

:Incredibly funny
:Figure skating
:Horizontal bar
:Equestrian
:BMX freestyle
:Pommel horse
:[Cueball tries to balance himself on a pommel horse. His both hands and one leg are down, while the other leg is slightly raised.]
:Cueball: Look! Look!
:[A horse rider wearing a black helmet is struggling to maintain balance on the running horse, with both hands and one leg raised.]
:Horse rider with black helmet: AAAAA!

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Sport]]

2962: President Venn Diagram

2024-07-23T10:55:26Z

172.68.186.90: /* Explanation */

{{comic
| number = 2962
| date = July 22, 2024
| title = President Venn Diagram
| image = president_venn_diagram_2x.png
| imagesize = 445x398px
| noexpand = true
| titletext = Hard to imagine political rhetoric more microtargeted at me than 'I love Venn diagrams. I really do, I love Venn diagrams. It's just something about those three circles.'
}}

==Explanation==
{{incomplete|Created by 2,382,203 Massachusetts write-in ballots for Randall Munroe - Please change this comment when editing this page. Do NOT delete this tag too soon.}}
{{notice|This whole comic contains just one opinion as interpreted by [[Randall|the comic's author]] about someone who, at the time of writing, is just one possible candidate amongst various others.
Please do not add anything to the main article that might be your own personal political opinion, and take similar care when making changes. This is not a rolling-news channel or debating room. Consider that readers in weeks/months/years to come, ''including yourself'', might understand or interpret contemporary 'facts' in a completely differently manner.|image=warning!!.png|**NB. This warning should probably remain for as long as Harris is candidate(-presumptive) in both Democratic and 2024-Presidential terms. Once this process concludes, one way or another, then the comic explanation is more safely subject to considered hindsight. Or perhaps now an ongoing incumbancy/positioned to await 2028, with a different pace of political advocacy/discountenance that might need a different form of warning.}}

This comic features a three-way {{w|Venn diagram}} (which [[2721: Euler Diagrams|is also an Euler diagram]]). The three circles represent {{w|President_of_the_United_States#Eligibility|eligibility for US presidency}}, qualification for US presidency, and love for Venn diagrams. According to Article II of the {{w|U.S. Constitution}}, someone is eligible for the presidency if they are a natural-born citizen of the United States, are at least 35 years old, and are a resident in the United States for at least 14 years. Both [[Randall Monroe]] and US Vice President {{w|Kamala Harris}} meet these qualifications.

Randall is known for his love of Venn diagrams, which feature heavily on xkcd. In this comic he implies that one reason why he is likely to support Kamala Harris for president is her alleged love of Venn diagrams, which she shares with Randall.

Current (as of the comic's publishing) Vice President Kamala Harris is the likely {{w|Democratic_Party_(United_States)|Democratic Party}} nominee for the 2024 election, following current President {{w|Joe Biden}}'s ending of his campaign the day before this comic's release. Kamala's love for Venn diagrams is something of a meme, and has been used by her in her campaign [https://www.independent.co.uk/news/world/americas/us-politics/kamala-harris-campaign-memes-gen-z-b2583802.html]

Randall has previously supported a presidential candidate in [[I'm With Her]].

The title text [https://www.youtube.com/watch?v=eWR2uTfrh-k quotes Kamala Harris on her affection for Venn diagrams], and implies that the best way to target Randall with political ads is to mention how amazing Venn diagrams are.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
A Venn diagram with three circles. 
Upper left circle: "Eligible to be President" 
Upper right circle: "Would be a good President" 
Lower circle: "Unusually vocal about love of Venn diagrams" 
Intersection of all three circles: "Kamala Harris" 
Intersection of the upper left and lower circles: "Me"

{{comic discussion}}
[[Category: Venn diagrams]]
[[Category: Politics]]
[[Category: Elections]]
[[Category: Comics featuring politicians]]