Talk:2034: Equations - Revision history

194.199.25.87 at 17:32, 18 June 2025

2025-06-18T17:32:37Z

172.71.23.217 at 19:09, 8 October 2024

2024-10-08T19:09:13Z

Rebecka: comment to kinematics - mention of michaelis-menten kinetics

2022-01-03T06:46:58Z

comment to kinematics - mention of michaelis-menten kinetics

Jezza2 at 16:03, 24 January 2019

2019-01-24T16:03:15Z

141.101.77.104: commented

2019-01-19T12:19:43Z

commented

Lysdexia: remove 2034 from the incomplete notice

2019-01-05T01:42:49Z

remove 2034 from the incomplete notice

172.69.226.83: Chemistry equation, OH- clarification

2018-12-30T19:55:39Z

Chemistry equation, OH- clarification

162.158.91.59: added $tag$

2018-12-05T18:55:02Z

added <math> tag

162.158.91.59: Added mention of partial derivative, gradient and curl operators in fluid dynamics equation.

2018-12-05T18:53:21Z

Added mention of partial derivative, gradient and curl operators in fluid dynamics equation.

Prstq: Some maths and number theory.

2018-09-16T15:54:35Z

Some maths and number theory.

@@ Line 85: / Line 85: @@
 If explainxkcd.com is to make XKCD comics more understandable then this explanation is failing that. I assumed from the beginning that the joke was about the equations being wrong, but the description of the joke is making my head hurt. {{unsigned ip|162.158.106.216}}
 :Read the first paragraph: "To someone who knows even a little about the topic, they are clearly very wrong and only seem even worse the more you look at them." Nevertheless the rest sometimes does hurt. See below. --[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 20:28, 17 August 2018 (UTC)
 ;All truly deep physics equations

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	Why does the notice still say 2034 lacks a complete explanation when here's no incomplete template? [[User:Lysdexia\|Lysdexia]] ([[User talk:Lysdexia\|talk]]) 01:42, 5 January 2019 (UTC)		Why does the notice still say 2034 lacks a complete explanation when here's no incomplete template? [[User:Lysdexia\|Lysdexia]] ([[User talk:Lysdexia\|talk]]) 01:42, 5 January 2019 (UTC)
	: Missing alt-text [[Special:Contributions/141.101.77.104\|141.101.77.104]] 12:19, 19 January 2019 (UTC)		: Missing alt-text [[Special:Contributions/141.101.77.104\|141.101.77.104]] 12:19, 19 January 2019 (UTC)
		+
		+	"Failed to parse (Missing <code>texvc</code> executable. Please see math/README to configure.): \oint" Searched it up, looks like a MediaWiki internal error, can we fix this? [[Special:Contributions/172.71.23.217\|172.71.23.217]] 19:09, 8 October 2024 (UTC)

@@ Line 104: / Line 104: @@
 ;Kinematics equations
 I fixed an error: Randall's Greek "rho" ''&rho;'', a common symbol for mass density, was incorrectly shown here as ''p'', the common symbol for momentum. The term with the ''&rho;'' is very similar to a term in the Bernoulli equation, and I have changed the explanation to reflect this. [[User:Redbelly98|Redbelly98]] ([[User talk:Redbelly98|talk]]) 00:40, 18 August 2018 (UTC)
 ;You might be overthinking some of these

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	I'd thought the point of the "u" with the cedilla was simply visual (not a reference to an actual parameter). It visually looks like the head of "The Thinker" in profile with the bottom of the "u" being the chin and the cedilla being the curled hand upon which the chin rests. So, the joke would be a twist on the term "deep" where in the cartoon the u+cedilla represents deep thought rather than far away (deep) into space. Monroe likes these little visual puns.[[User:Genejockey33000\|Genejockey33000]] ([[User talk:Genejockey33000\|talk]]) 14:01, 22 August 2018 (UTC)		I'd thought the point of the "u" with the cedilla was simply visual (not a reference to an actual parameter). It visually looks like the head of "The Thinker" in profile with the bottom of the "u" being the chin and the cedilla being the curled hand upon which the chin rests. So, the joke would be a twist on the term "deep" where in the cartoon the u+cedilla represents deep thought rather than far away (deep) into space. Monroe likes these little visual puns.[[User:Genejockey33000\|Genejockey33000]] ([[User talk:Genejockey33000\|talk]]) 14:01, 22 August 2018 (UTC)
		+
		+	I don't like the comparison with <math>E=mc^2</math>. 'Deep' physics equations have a lot of meaning assigned to each symbol, with each prime, tilde or cedilla adding meaning, and with complicated operations implicit (Think operators, tensor products etc.). Einstein's relation is just a relation between 3 scalar variables, with the only operation being multiplication. I appreciate not wanting to get too complicated. Can we do any better? I can't help thinking that writing down the GFEs in natural units and saying 'this describes all of spacetime' owtte would be just as effective and more accurate...[[User:Jezza2\|Jezza2]] ([[User talk:Jezza2\|talk]]) 16:03, 24 January 2019 (UTC)

	;Table layout at the explanation		;Table layout at the explanation

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	Why does the notice still say 2034 lacks a complete explanation when here's no incomplete template? [[User:Lysdexia\|Lysdexia]] ([[User talk:Lysdexia\|talk]]) 01:42, 5 January 2019 (UTC)		Why does the notice still say 2034 lacks a complete explanation when here's no incomplete template? [[User:Lysdexia\|Lysdexia]] ([[User talk:Lysdexia\|talk]]) 01:42, 5 January 2019 (UTC)
		+	: Missing alt-text [[Special:Contributions/141.101.77.104\|141.101.77.104]] 12:19, 19 January 2019 (UTC)

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 :Looks like it. But I don't think that letter exists even. --[[Special:Contributions/162.158.91.221|162.158.91.221]] 07:28, 17 August 2018 (UTC)
 :Is this equation a sort of nod to a Theory Of Everything which unifies quantum mechanics and gravity... H-hat (a Hamiltonian,  which in quantum mechanics describes the total energy of a system, and usually runs in to problems describing large systems - such as the entire universe - where gravity or spacetime curvature effects matter) *minus* u0 (the relativistic mass of the whole system at time zero ie. the big bang) gives 0 (no energy everywhere always). Since mass is energy (e=mc^2) and mass is also the sole cause of gravity the two theories cleanly collapse together when mass is zero, and figuring out how to extend the theory to other less clean points on the mass axis is obviously a job for less profound physics? I've no ideas to explain the cedilla. [[Special:Contributions/141.101.98.28|141.101.98.28]] 08:49, 17 August 2018 (UTC)
 :It looks to me a little like a parody of the {{w|Wheeler-DeWitt_equation#Hamiltonian_constraint|Wheeler-DeWitt equation}} which (in theory) describes a wavefunction for the entire Universe. [[User:Exxi|Exxi]] ([[User talk:Exxi|talk]]) 09:06, 17 August 2018 (UTC)一
 : I'm just thrilled someone found the right character for it. I spent 20 minutes looking for the right u symbol without any luck at all. {{unsigned ip|172.68.143.132}}
 Is this poking fun at equation-filled blackboards in movies and cartoons? {{unsigned ip|172.68.254.42}}
 :Doesn't seem like it. These equations actually do look like the kinds of equations you would see in these fields. On blackboards in movies you tend to get equations that are pure nonsense. {{unsigned ip|172.68.143.132}}
 I think this may also be a reference to Feynman's unworldliness equation, http://www.feynmanlectures.caltech.edu/II_25.html#Ch25-S6 . [[Special:Contributions/108.162.219.220|108.162.219.220]] 17:02, 17 August 2018 (UTC)
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 :::Infinite is NO number! --[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 17:33, 17 August 2018 (UTC)
 ::::<math>\infty-\infty</math> is indeterminate, just like 0/0 is in standard arithmetic. That's cool, because we don't need the value of <math>\infty-\infty</math> to calculate the above expression. Have a look at the [https://en.wikipedia.org/wiki/Extended_real_number_line extended real number line]. --[[User:Ycthiognass|Ycthiognass]] ([[User talk:Ycthiognass|talk]]) 06:18, 20 August 2018 (UTC)
 :Number theorists use <math>\pi</math> and <math>e</math> very often indeed, especially analytic number theorists (and since the double sum at hand is infinite it seems entirely fair to consider it analytic number theory territory). The exponential function <math>e(x) = e^{2 \pi i x}</math> is used all over in this field because of Fourier series (the coefficients of which, it turns out, can give remarkable amounts of arithmetic information if used properly).
 :The same field of analytic number theory uses the infinity symbol <math>\infty</math> in calculations quite frequently too, because it is not uncommon to work on the Riemann sphere, which is the complex plane with a "point at infinity added". (That said, it doesn't quite save our hides in this particular comic, because the point at infinity doesn't have an additive inverse in this context.)
 :For the record there are also numerous ways to extend the real numbers to include infinities in more or less algebraically nice ways, ranging from compactifying it by just tacking a point at infinity on (as with the Riemann sphere for the complex numbers, also called a projective extension), tacking a positive and negative infinity on as with the extended real line as above, to more algebraically nice structures like the hyperreals and surreals which are full blown fields. In these latter constructions it is not customary to use the <math>\infty</math> symbol, however, because there is more than just the one infinity in both, but they do allow us to make meaningful and useful sense of things like "infinity - infinity". [[User:Prstq|Prstq]] ([[User talk:Prstq|talk]])
 Completely separate from the above, it's probably worth noting that i is also a constant, and as such has the same misconception as <math>\pi</math>. Computer scientists are happy using i for loops/summations, but mathematicians prefer using n. Based off that, it's probably another misconception/joke that n is treated as a constant, while known-constants are used as variables. [[Special:Contributions/108.162.246.149|108.162.246.149]] 17:28, 17 August 2018 (UTC)
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 Although you could write HeAt (Helium-Astatine), I could find no element symbols to form EAT on the right-hand side of the reaction, so it appears to be an invalid expression anyway. (and yes, of course I know Randall is messing with us and you might be expected to read the first "heat" as "temperarature".) --[[User:IByte|IByte]] ([[User talk:IByte|talk]]) 11:17, 4 September 2018 (UTC)
 : And Randall wrote HEAT, not HeAt. They are different. [[User:Redbelly98|Redbelly98]] ([[User talk:Redbelly98|talk]]) 18:33, 9 September 2018 (UTC)

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	The methyl group can dissolve in water, and this is presumably happening in water, so this equation can work, just not the one provided by Randell. Reacting longer alkanes with bases is a way to make soaps, but the methyl group would be too reactive to be used this way. [[User:Nutster\|Nutster]] ([[User talk:Nutster\|talk]]) 13:13, 17 August 2018 (UTC)		The methyl group can dissolve in water, and this is presumably happening in water, so this equation can work, just not the one provided by Randell. Reacting longer alkanes with bases is a way to make soaps, but the methyl group would be too reactive to be used this way. [[User:Nutster\|Nutster]] ([[User talk:Nutster\|talk]]) 13:13, 17 August 2018 (UTC)
		+	OH without any charge is the hydroxil radical, a highly reactive moleculte, that in fact abstracts H (hydrogen atom, not a proton) from hydrocarbons. This is one step of combustion processes. The methyl radical generated combines itself quickly with oxygen.
		+	The hydroxide anion you propose OH<sup>-</sup> do not react with hydrocarbons.

	;Fluid Dynamics equation		;Fluid Dynamics equation

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 I changed a "p" to a Greek "rho". [[User:Redbelly98|Redbelly98]] ([[User talk:Redbelly98|talk]]) 00:40, 18 August 2018 (UTC)
-The \frac{\partial}{\partial t} is the partial derivative of a function. The ∇ symbol (Nabla) denotes the vector of all partial derivatives of a function (called its gradient; eg. ∇(x+2y²)=(1,4y) ); ∇⋅ is the curl operator. [[Special:Contributions/162.158.91.59|162.158.91.59]] 18:53, 5 December 2018 (UTC)
+The <math>\frac{\partial}{\partial t}</math> is the partial derivative of a function. The ∇ symbol (Nabla) denotes the vector of all partial derivatives of a function (called its gradient; eg. ∇(x+2y²)=(1,4y) ); ∇⋅ is the curl operator. [[Special:Contributions/162.158.91.59|162.158.91.59]] 18:53, 5 December 2018 (UTC)
 ;Gauge theory equation
 <s>I think the transcript is missing a left superscript 0 before the turned xi.  [[Special:Contributions/172.68.226.16|172.68.226.16]] 16:50, 17 August 2018 (UTC)</s>  Ah no, sorry.  False alarm.  It's just that Randall writes the xi with a funny tail.  The same tail is on the non-turned xi earlier.  [[Special:Contributions/172.68.226.10|172.68.226.10]] 16:52, 17 August 2018 (UTC)