Editing Talk:1184: Circumference Formula

Tau x Radius, superscript 2
:Since tau is more commonly used for the Golden Ratio, that's a silly idea. [[Special:Contributions/121.74.169.237|121.74.169.237]] 11:13, 23 September 2013 (UTC)
::You may be confusing tau with phi. I've never seen the golden ratio represented by anything other than phi. I've also never seen tau representing anything other than 2pi. [[Special:Contributions/108.162.219.7|108.162.219.7]] 19:25, 10 May 2014 (UTC)

:Leaves one wondering what the superscript 1 refers. {{unsigned|‎74.215.40.250}}
::It's 2''&pi;r''<sup>2</sup>, '''not''' ''&tau;r''<sup>2</sup>. —[[Special:Contributions/173.199.215.5|173.199.215.5]] 05:37, 11 March 2013 (UTC)
:::You're missing the point. ''&tau;'' == 2''&pi;'' and is considered better than using ''&pi;'' by some people {{unsigned|138.195.69.136}}
::::Only for very loose definitions of "better." [[Special:Contributions/71.201.53.130|71.201.53.130]] 14:59, 11 March 2013 (UTC)
::::Whoa! Never heard about that before, but after 2 hrs or so, I think I'm getting convinced! Check this site out: http://tauday.com/ What do you think? –[[User:St.nerol|St.nerol]] ([[User talk:St.nerol|talk]]) 18:06, 11 March 2013 (UTC)

::I think tau is pointless.  Using tau what then happens to Euler's famous formula, the most beautiful equation of them all?  Pi shows up in so many different ways and places in mathematics.  Tau appears pretty much only in the formula for a circle's circumference.  Why bother needlessly proliferating symbols? [[User:J Milstein|J Milstein]] ([[User talk:J Milstein|talk]]) 18:17, 11 March 2013 (UTC)
::: Surface area of a sphere is 2τr^2, or if you want to get pi in there ''&pi;''d^2 {{unsigned ip|108.162.218.101}}

:::RE: Euler's Identity: e^(tau*i) - 1 = 0 --[[User:Max Nanasy|Max Nanasy]] ([[User talk:Max Nanasy|talk]]) 18:27, 11 March 2013 (UTC) 
::::Ok, that works [[User:J Milstein|J Milstein]] ([[User talk:J Milstein|talk]]) 17:05, 13 March 2013 (UTC)
::::Why not just e^(tau*i) = 1. Do you routinely do 2 + 2 - 4 = 0?[[Special:Contributions/206.181.86.98|206.181.86.98]] 20:31, 13 March 2013 (UTC)
:::::Because:
:::::* Symmetry wrt the original Euler's Identity (e^(pi*i) + 1 = 0)
:::::* According to http://en.wikipedia.org/wiki/Euler's_identity#Mathematical_beauty, "in algebra and other areas of mathematics, equations are commonly written with zero on one side of the equals sign."
:::::--[[User:Max Nanasy|Max Nanasy]] ([[User talk:Max Nanasy|talk]]) 00:35, 14 March 2013 (UTC)
::::::I think Euler only did that because he disliked negative numbers. It really is less a deal than people make of it.[[Special:Contributions/206.181.86.98|206.181.86.98]] 03:02, 15 March 2013 (UTC)
:::::::Also, it uses the five most important constants in mathematics: ''e'', ''π'' (or ''τ''), ''i'', 1, and 0. [[User:Curtmack|Curtmack]] ([[User talk:Curtmack|talk]]) 20:33, 30 April 2013 (UTC)
::::The tau variant of Euler's identity above, ''e^(tau*i)=1'', appears to miss the point. Normally, a positivt number to the power of any real number is positive. Thus ''i'' could be any normal number. Well, not any number. ''i'' could be 0 and the equation will hold. With pi however, ''e^(pi*i)=-1'', ''i'' must be magical. /David A [[Special:Contributions/141.101.80.111|141.101.80.111]] 23:53, 9 November 2013 (UTC)
:::[http://tauday.com/tau-manifesto The tau manifesto] fairly well convinced me that all occurances of &pi; in mathematics utimately trace back from the formula C = 2''&pi;r''. If so, &pi; naturally ''enter'' calculations as 2&pi;. Can anyone find a counterexample to this thesis? –[[User:St.nerol|St.nerol]] ([[User talk:St.nerol|talk]]) 00:29, 14 March 2013 (UTC)
::::How could there be a counter-example? I think it is true. In complex analysis, it really should be 2&pi;, and thus Gaussian integrals. And then number theory applications. Even [http://www.jstor.org/discover/10.2307/2589152?uid=3739704&uid=2&uid=4&uid=3739256&sid=21101976916347 this] neat result really stems from trig identities, so it really is a result for 2&pi;. [[Special:Contributions/206.181.86.98|206.181.86.98]] 02:59, 15 March 2013 (UTC) 
:From what I understand, the thesis from the tau-proponents is that 2*pi is the fundamental natural constant, and that virtually ''every time'' that pi shows up without the factor 2, there originally was a factor two that was cancelled out.  –[[User:St.nerol|St.nerol]] ([[User talk:St.nerol|talk]]) 01:53, 12 March 2013 (UTC)
:For everyone who suddenly started a debate about 2pi and tau: http://xkcd.com/1292/ [[Special:Contributions/108.162.222.61|108.162.222.61]] 06:58, 4 May 2014 (UTC)

Not completely sure Earth Prime is from Sliders, but it's true it's the [http://en.wikipedia.org/wiki/Earth_Prime only one named exactly that] ... -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 09:54, 11 March 2013 (UTC)

There's also a [http://dc.wikia.com/wiki/Prime_Earth Prime Earth] now. Just so DC can screw with us. [[User:Hogtree Octovish|Hogtree Octovish]] ([[User talk:Hogtree Octovish|talk]]) 10:40, 11 March 2013 (UTC)


I still don't get it.[[Special:Contributions/49.176.102.213|49.176.102.213]] 12:41, 11 March 2013 (UTC)

:If you don't get it, you don't need to get it [[User:J Milstein|J Milstein]] ([[User talk:J Milstein|talk]]) 18:07, 11 March 2013 (UTC)

Well, that was lame. --[[Special:Contributions/87.122.60.227|87.122.60.227]] 17:19, 11 March 2013 (UTC)


This comic illustrates the strategy of "The Unconsummated Asterisk", from the essay "Mathmanship" by Nicholas Vanserg (available at [http://e-science.ru/forum/index.php?act=attach&type=post&id=7701]).
<blockquote>
The other side of the asterisk gambit is to use a superscript as a key to a real footnote. The knowledge‐seeker reads that S is – 36.7<sup>14</sup> calories and thinks "Gee what a whale of a lot of calories" until he reads to the bottom of the page, finds footnote 14 and says "oh."
</blockquote>
For bonus points, Randall could have used also "Pi-Throwing":
<blockquote>
For example every schoolboy knows what &pi; stands for so you can hold him at bay by heaving some entirely different kind of &pi; into the equation. The poor fellow will automatically multiply by 3.1416, then begin wondering how a &pi; got into the act anyhow, and finally discover that all the while &pi; was osmotic pressure. If you are careful not to warn him, this one is good for a delay of about an hour and a half.
</blockquote> [[User:Chymicus|Chymicus]] ([[User talk:Chymicus|talk]]) 19:01, 11 March 2013 (UTC)
:Another good one is &pi; as a symbol for profit in financial discussions. -<span style="background-color: #bbbbff;">[[User:DrGaellon|DrGaellon]] <span style="font-size: smaller;">([[User talk:DrGaellon|talk]] &#124; [[Special:Contributions/DrGaellon|contribs]])</span></span> 23:23, 25 March 2013 (UTC)

I believe the current description of prime as denoting derivatives is true but irrelevant. Since the area and circumference refers to geometry (not really calculus), it's more likely that the title text is referring to the common use of primes in geometry.  For example, there might be two or more parallel lines that are denoted by x, x′, x′′, etc.  Wikipedia also notes another geometric use of {{w|prime}}: "if a point is represented by the Cartesian coordinates (x, y), then that point rotated, translated or reflected might be represented as (x′, y′)." [[User:S|S]] ([[User talk:S|talk]]) 23:32, 11 March 2013 (UTC)

that is so wrong, i feel my mind corrupted now. -- [[User:Anarcat|Anarcat]] ([[User talk:Anarcat|talk]]) 23:57, 11 March 2013 (UTC)


This explanation was hillarious -- where is the up-vote button ?? [[User:Spongebog|Spongebog]] ([[User talk:Spongebog|talk]])

:+1 [[User:Smperron|Smperron]] ([[User talk:Smperron|talk]]) 16:33, 13 March 2013 (UTC)

So, where's todays comic? How many times has Randal been late?[[Special:Contributions/70.199.225.225|70.199.225.225]] 16:15, 13 March 2013 (UTC)

:Today's comic was posted just a few minutes ago. I'm anxiously awaiting its explanation as it picks on a programming language I'm not familiar with (possibly SQL). [[User:Smperron|Smperron]] ([[User talk:Smperron|talk]]) 16:33, 13 March 2013 (UTC)

It uses pseudocode.  The new one is about sorting algorithms in general, not any particular language.  [[Special:Contributions/130.245.231.101|130.245.231.101]] 17:00, 13 March 2013 (UTC)

Perhaps it's just me, but did no one see the "square the circle" gag...? --[[Special:Contributions/128.232.142.37|128.232.142.37]] 09:24, 14 March 2013 (UTC)  No one but you saw the square-the-circle gag, because it's not there.  For it to be there, it would require this: (2πr)² [[User:J Milstein|J Milstein]] ([[User talk:J Milstein|talk]]) 15:31, 14 March 2013 (UTC)

This one threw me for a loop for the longest time because I learned to use πd to find circumference, not 2πr. Anyone else learn that way? (Knowing how my brain works, it is equally possible I taught myself to use πd as a shortcut, and was in fact taught 2πr by my teachers.) [[User:Boct1584|Boct1584]] ([[User talk:Boct1584|talk]]) 22:20, 31 March 2015 (UTC)

I thought the joke in the title text was that primes can refer to successive derivatives. [[Special:Contributions/108.162.221.150|108.162.221.150]] 05:05, 19 August 2015 (UTC)

: I support this. r' can be the derivative of r = angular speed, r" the double derivative of r = angular acceleration. The joke is that r' and r" are horrible notations, because they are already have two meanings, giving them yet another meaning beyond derivative and "r measured in different frame of reference" would add to the existing confusion. [[User:MigB|MigB]] ([[User talk:MigB|talk]]) 09:04, 7 December 2021 (UTC)

Ok, but the 2nd sentence in the explanation has a grammar mistake. The sentence reads, "Randall then makes a footnote about r, using." In this case "²" is an indication for a footnote, isn't it ? {{unsigned ip|162.158.83.240}}

== Amicable numbers ==
1184 is one of them that are discovered relatively rather late. The other one [[1210]] (very close to [[1208]]) is also math-related.