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Add
in the section under
"See also"
LynneMD80 ( talk) 01:55, 6 June 2011 (UTC)
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Yazzcoat (
talk)
11:50, 12 June 2011 (UTC)
ARITHMETIC PII
Surround rooms, living rooms witch is circle, what have bossebility know square meter. 6 meter long diameter 6x 2 × pii = m2 12 x 3,14 = 37,68m2.
8 meter long, diameter = 8 multiplication 2 x pii ( 8x 2 x 3,14) = m2.
10,000 Colors of Pi
Suggest addition of this link:
http://www.donnelly-house.net/funcrec/picolors/ — Preceding unsigned comment added by 24.10.49.212 ( talk) 22:34, 6 July 2011 (UTC)
suggestion, adding that the first 3 digits of pi, when looked at in a mirror, resemble the English word pie. — Preceding
unsigned comment added by
75.104.47.201 (
talk)
20:13, 22 July 2011 (UTC)
I've removed the claim that pi appears in formulas that have no relationship to Euclidean geometry. It was incorrectly cited, but I think more importantly, it's misleading. All the formulas we give as examples _are_ related to Euclidean geometry in the sense that they use pi to calculate density functions (abstracted from geometry), or to enable translations between linear and radial measurements. My concern is that we are suggesting that pi is a _physical_ constant, which arguably it isn't. Perhaps this distinction should be clarified more in the text? But from the list of examples, it is clear that pi gets used in a diverse range of places. Ethan Mitchell ( talk) 20:37, 6 August 2011 (UTC)
In his book The Riddle of the Pyramids, physicist Kurt Mendelssohn notes the relations to pi in the measurements of the Pyramids. He proposes that since we know the Egyptians did not achieve the value of pi until much later than the building of the pyramids, that the relationships most likely originate in pragmatic building techniques. He notes that the Egyptians couldn't have used ropes to measure long distances, because they stretch, and that a good solution is to count the number of revolutions of wooden drum. If you make the diameter of the drum, for example, one cubit, and then make the base the same number of "rolled" cubits as you make the height in "regular" cubits, then the relationship to pi emerges by itself, as a consequence of the tools used. You can find the reference in Chapter Three of Mendelssohn's book, "The Unsolved Problems." In my paperback edition (Cardinal, 1976, from the 1974 Thames & Hudson edition), the discussion is on PP76-79, where the proposal is sourced to electrical engineer T.E. Connolly. — Preceding unsigned comment added by Theonemacduff ( talk • contribs) 23:13, 23 August 2011 (UTC)
Can we please put the image File:Pi-unrolled-720.gif back in the lead, where it was when the article received GA status? I'm aware, of course that User:Anythingyouwant is, for whatever reason, opposed to this image. But it is the simplest and best picture illustrating the meaning of π, which is traditionally defined as the ratio of the circumference of a circle to its diameter. It does this without any equations, and so is accessible to the most naive reader. By contrast, the new lead images favored by User:Anythingyouwant both require equations of some form to understand, and so are going to be less accessible for a large number of potential readers (which is likely to include grade-school geometry students less comfortable with abstract equations). There has been consensus for this lead image in the past. I would like to put it back in. Let me know what you think. Sławomir Biały ( talk) 00:33, 17 September 2011 (UTC)
The images are somewhat better after recent edits, but I would still prefer (for reasons already articulated) to have the animation at the top. Sławomir Biały ( talk) 14:44, 17 September 2011 (UTC)
I agree that the "pi unrolled" animation is a good image, and it deserves to be part of the article. But I feel uneasy about having an animation right at the top of the page. I think the main focus of the lead should be the text, not moving pictures. Jowa fan ( talk) 03:42, 18 September 2011 (UTC)
What is the point of the infobox showing pi in multiple bases etc.? The best rational approximations are helpful, and I can sorta see the point of having binary and continued fractions, simply to show that there's no obvious pattern of the digits, but why octal, hexadecimal, and sexagesimal? They don't give any useful insight, and have no practical value. You might think the sexagesimal represention has some antiquarian value because of the Babylonian use of sexagesimal, but apparently the Babylonians didn't calculate with pi as a sexagesimal fraction (and certainly not to so many digits), but as the fraction 25/8 (not even 22/7). -- Macrakis ( talk) 14:37, 17 September 2011 (UTC)
Huh???? Sexagesimal is not notable, although it was used in Ptolemy's Almagest, but base-11 is notable because it appeared in some obscure novel?? I don't see any great need for so MANY digits in base-60 as what we saw there, but it's historically significant that base-60 was once standard in some eastern Mediterranean countries and was used in the most famous of all books ever written on astronomy. Michael Hardy ( talk) 02:18, 18 September 2011 (UTC)
Some time later this month it will become possible to write two archaic Greek letters in TeX in Wikipedia articles. Those two letters were used in Ptolemy's Almagest in the numeral system he used, with base 60 and subbase 10. So after that I will go check out his book from the library again, and do some further editing of the article about his table of chords. At that time, I will see exactly what he says about π, and probably say something about it in this article. Michael Hardy ( talk) 22:15, 18 September 2011 (UTC)
I like to say that first off Wikipedia is an encyclopedia, not a course in advanced astrophysics. Even so calculating Pi() to 40 digits would suffice in all possible uses in astrophysics. This page is deeply flawed in its emphasis. Pi critical function is in defining circular parameters and derivation of trigonometric phenomena. Pi, for instance, tells us the number of radians in a circle. E.g. (180/pi() = 1 radian in degrees). The radian is essential for the calculation of sines and cosines based on alpha, because it defines how many radians there are in a circle and because it makes if possible for us to relate angles in radians to angles commonly used in daily life (30, 45, 60, 90, 120, etc.). Several aspects of the mathematical usefulness of pi are virtually glossed over for this numerology which is nothing more than amateur science taken to an extreme. Most pages would place 80% of whats on this page into a paragraph "Pi in popular culture". This page is on the same caliber as the Apollo 16 page.
pi/2 = 90 (an arbitrary base 360' system in which is better based on the pi/radian based system) pi/3 = 60', in a right triangle the adjacent side is 1/2 the hypotenuse. pi/4 = 45', in a right triangle both the opposite and adjacent sides are equal, and the length is 1/(2^0.5) the hypotenuse pi/6 = 30', in a right triangle the opposite side = 1/2 the hypotenuse.
This page is an excellent example of the fact that mathematics is not a pure science, but a representative language-tool for science. Pi() has scientific meaning in that its properties supercede base-systems. But knowing the digital representation in base 10 is therefore meaningless, even less meaningful in the age of computers when its precision is arbitrarily set to 8, 16, 32, or 64 digits and can be implemented without any knowledge using terms like pi(). Memorizing 100,000 digits is even more meaningless. These numerologistic analysis are the equivelant of a page on supercalifragilisticexpialidosious. PB666 yap 22:13, 14 October 2011 (UTC)
Just saw that another calculation has it to 10 trillion digits. http://www.numberworld.org/misc_runs/pi-10t/details.html — Preceding unsigned comment added by 67.169.191.53 ( talk) 03:46, 20 October 2011 (UTC)
Yeah, by the same guys:
Ricardobeat ( talk) 18:39, 22 October 2011 (UTC)
It should be on the left or on the right, but not both sides, eh? 68.2.46.143 ( talk) 20:21, 11 November 2011 (UTC)
I've inserted a slightly modified top image. I made it myself, so the quality isn't so good. But, I've submitted a request to the image gurus to fix it up. Anythingyouwant ( talk) 19:27, 18 September 2011 (UTC)
I like this image a lot. — Preceding unsigned comment added by 173.66.156.8 ( talk) 15:19, 13 November 2011 (UTC)
I saw that the 50 decimal representation of π I added to the lead section was removed. I think it should be there, and I reason like this:
Many times when people visit this article, it is only to get an accurate numerical value of π, why it is important that the value is easy to find. Therefore, it should be in the lead section of the article, or at least somewhere close to it so it can be seen immediately when the article is loaded. For example, I usually use Wikipedia to look up both physical and mathematical constants when I need them for either programming or for calculations. In those cases, I don't want to have to look through a large part of the article in order to find the numerical value, and for π, 3.14 is simply not enough. — Kri ( talk) 01:09, 16 November 2011 (UTC)
Yes, "its decimal representation never ends or repeats indefinitely" is vague compared to a longer explanation like "... repeats infinitely like 5/6=0.8333333 ... or 3/22=0.13636363636 ...". But "repeats indefinitely" is less vague than just "repeats", which is simply wrong; the decimal representation does repeat finitely. Art LaPella ( talk) 06:35, 10 October 2011 (UTC)
There's recently been an edit war regarding the content of Pi#Alternative_notation. My feeling is that we already have an article for Tau (2π), so there's no need to repeat too much of that content here. I'm concerned that appears in the current version reads like an advertisement for the use of tau: it gives undue weight to this notation. I'd prefer to see this section cut right back: people can go to the main article if they want to learn more. Jowa fan ( talk) 03:21, 17 November 2011 (UTC)
I replaced the summary with new text which explains the rationale under the introduction of the new constant. (The question "why" pops up immediately and naturally.) Max Longint ( talk) 02:18, 18 November 2011 (UTC)
Nobody posted any objections, so I have changed the section title to "Tau as an alternative circle constant". I will monitor this Talk page for the next few days, so please post any new objections here instead of just reverting my edit. I'll be sure to respond promptly. And I'm still eager to hear any thoughts you have on whether tau is the best circle constant, versus whether pi or tau is better everywhere else. Thanks. Joseph Lindenberg ( talk) 22:40, 18 November 2011 (UTC)
The history section of this article claims a source, which makes an inaccurate assumption from the Bronze Sea description in 1Kings 7:23-26. The description in 1Kings includes that "the walls were sloped like a lily" showing taper.
If the bronze sea was vertically walled, pi=3 would stand, but it's approximately a frustum of a cone. A simple description is shown at the following link: http://www.yihyeh.com/the-bronze-sea.html
Since the value of a bath is known, and the number of baths that the bronze sea held is known, determining the volume provides a great estimate of the value of a biblical cubit. The key is that the simplest number of measurements is given, as expected when manufacturing screws or any crude form that was tapered. No938 ( talk) 04:16, 27 November 2011 (UTC)
In the article it says:
When used as a symbol for the mathematical constant, the Greek letter (π) is not capitalized at the beginning of a sentence. The capital letter Π (Pi) has a completely different mathematical meaning; it is used for expressing the product of a sequence.
Yet in the article, the capital 'Π' instead of 'π' is used consistently at the start of sentences. Do we not contradict ourselves? Is there a problem with {{pi}}? Kleuske ( talk) 09:16, 10 December 2011 (UTC)
As far as I can tell, this hasn't been discussed recently, but I thought use of {{ frac}}, such as in the section Pi#Estimating the value, is discouraged in mathematical articles, per WP:MOSMATH. — Arthur Rubin (talk) 16:07, 10 December 2011 (UTC)
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hi i want to edit this wiki page as i have the first 100,000 didgets of pi in a txt document which i can put a link to on my current website http://skweekz.sexyi.am/upload/PI.txt
thanks for reading
p.s i would be happier if you would to deny this and edit the page yourself if thats no problem.
best regards richard aka skweekz
Skweekz ( talk) 14:10, 21 December 2011 (UTC)
I've added a hatnote to deal with capital Pi. Frankly, the lack of a hatnote to this effect was disgraceful... many readers of Wikipedia have not completed high school mathematics, and might be looking for this meaning; Most probably have, and would laugh at the current redirect even now we explain it.
See also Template talk:Hatnote templates documentation#Is there a suitable template for this. Andrewa ( talk) 19:41, 5 December 2011 (UTC)
Unfortunately that π and Π link to the same page is unavoidable as WP ignores the capitalisation of the initial letter. The question of which page belongs at π is a different one, and depends on which if anything is the primary topic for pi and π. One thing we can look at for this is pageview statistics:
The current page is overwhelmingly the article sought by users reaching here: few visit the disambiguation page after, and under 1% use the redirect Π to get here. So the current page is the primary topic and there is very little evidence readers are looking for another topic instead of the one here.-- JohnBlackburne words deeds 20:24, 6 December 2011 (UTC)
The pi value was given by the Indian mathematician ARYABHATA. — Preceding
unsigned comment added by
S.R.Aniruddha (
talk •
contribs)
17:00, 1 January 2012 (UTC)
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Typo for the caption under the digits of pi: "An calculation" should be "A calculation".
Deadwisdom ( talk) 22:07, 21 December 2011 (UTC)
On article there is equation for calculation of individual digits. I'm not sure about this because none of terms in sum has finite decimal representation, and I think hexadecimal representations are also infinite. So I think that to find digit N we must find Nth digit in first term, Nth digit in second term,...,Nth digit in (N-1)th term, and remainders from further digits. Because of this I think this method isn't to effective, but one simpler ones. This is rather question about mistake in my thinking, not any proof Wojowu ( talk) 17:32, 3 January 2012 (UTC)
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I was going to type that computers are still trying to get a non repeating number
Jcarcerano ( talk) 03:22, 7 January 2012 (UTC)
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Please add a link for "Ramanujan" (a mathematician who is mentioned in this article): there is a wikipedia page for him. http://en.wikipedia.org/wiki/Srinivasa_Ramanujan Eternal fizzer ( talk) 12:24, 20 January 2012 (UTC)
In the paragraph that starts, "In 1706 John Machin was the first ...", I find it perplexing that Machin attempts to compute π based on 4atan(1/5)-atan(1/239) when π/4 = atan(1). Surely, if he were sophisticated to do what is said, he should have known of the simpler formula. Ksn ( talk) 16:07, 15 February 2012 (UTC)
I'm planning on working on the article, with the ultimate goal of reaching WP:FA status. I've gotten a few books from the library, including π: A biography of the world's most mysterious number (by Posametier & Lehmann); and Pi Unleashed (by Arndt and Haenel). The article is already in decent shape (and is already GA status), with some great illustrations. The biggest jobs appear to be (1) ensuring that all material has a good source, per WP:V; and (2) ensuring that the article is comprehensive. Plus, making sure the prose is professional quality (not my strong suit). Any help, suggestions, sources, etc. would be appreciated. -- Noleander ( talk) 21:08, 8 March 2012 (UTC)
Well,it's because of the first 3 digits of π,3.14,it tell us that it's on 3/14 which is March 14. — Preceding unsigned comment added by 207.237.10.60 ( talk) 23:38, 14 March 2012 (UTC)
The first 1120 of Pi are:3.14159265358979323846264338327950288419716939937510582097494459230781640628620899862803482534211706798214808651328230664709384460955058223172535940812848111745028410270193 8521105559644622948954930381964428810975665933446128475648233786783165271201909145648566923460348610454326648213393607260249141273724587006606315588174881520920962829254091715 3643678925903600113305305488204665213841469519415116094330572703657595919530921861173819326117931051185480744623799627495673518857527248912279381830119491298336733624406566430 8602139494639522473719070217986094370277053921717629317675238467481846766940513200056812714526356082778577134275778960917363717872146844090122495343014654958537105079227968925 8923542019956112129021960864034418159813629774771309960518707211349999998372978049951059737328160963859502445945534690830264252230825334468503526193118817101000313783875288658 7533208381420617177669147303598253490428755468731159562863882353787593751957781857780532171226806613001927876611195909216420198938095257201065485863278865936153381827968230301 9520353018529689957736225994138912497217752834791315155748572424541506959 — Preceding unsigned comment added by 207.237.10.60 ( talk) 23:48, 14 March 2012 (UTC)
THis image was working before http://en.wikipedia.org/wiki/File:Pi-unrolled-720.gif Now it isn't. Is this a local problem? Picklebobdogflog ( talk) 00:18, 16 March 2012 (UTC)
For a mathematical constant as thoroughly studied as π, the section on renaming it to τ should not be here. It is a gross violation of WP:WEIGHT. Moreover, none of the sources referenced meet even the most minimal standards of scholarship needed for inclusion in an encyclopedia article. The symbol τ is not used in any mainstream mathematical sources. Sławomir Biały ( talk) 11:00, 19 March 2012 (UTC)
The two subsections " Representation as a continued fraction" and "Memorizing digits" are currently under the "History" top level section, which is not appropriate. I'll move them out to be top level sections for now, but that is not ideal, since that would lead to a lot of top level sections. This article may need a "Miscellaneous" top level section, to hold "Tau", "In Popular Culture", "Representation as a continued fraction" and "Memorizing digits" ... but "Misc" is not ideal either. Any thoughts? -- Noleander ( talk) 19:32, 17 March 2012 (UTC)
The History section has an Antiquity subsection; but before that is an intro paragraph about Egypt. Clearly, that Egypt material belongs in the Antiq section, so I'll move it.
There seem to be several "obvious" changes to make, similar to that, so I'll forge ahead without notifications here on the Talk page. If anyone sees a mistake, or does not agree with a particular change, feel free to revert. Or, better yet, just drop a quick note here on the Talk page and I'll remedy any issues. -- Noleander ( talk) 19:42, 17 March 2012 (UTC)
The pyramids section seems a bit verbose; and also a bit polemic, emphasizing the "they were based on pi" viewpoint. I suggest tightening that section a bit, and also relying more on secondary sources. I think the tone should be something like "Some egyptologists have speculated ..., but others view the proposal with skepticism ...". Thoughts? -- Noleander ( talk) 19:59, 17 March 2012 (UTC)
The Pi#Computer_era section has a large table of about 20 infinite sum equations for pi. This seems excessive. This article is a main article, with several subarticles. The kind of detail in that table should be moved down into a subarticle such as Approximations_of_π or List of formulae involving π. Of course, a few key formulae (from that table) could be left in this article if secondary sources specifically mention them prominently. Thoughts? -- Noleander ( talk) 14:51, 19 March 2012 (UTC)
When displaying incidental formulae, the article has the choice of placing them in between paragraphs (inline), or in a sidebar box. I have no preference one way or another, but as an experiment, I've placed a few on the side in the Pi#Infinite_series section. The convention in WP math articles seems to favor centering the formulae in-line. For instance the Logarithm article, a FA article within the Math project puts all its formulae inline. If anyone objects to this temporary formatting experiment, I can move them back in-line, no problem. At some point, before this is nominated for FA status, we'll have to decide on way or another. As I say, I have no preference on way or another, but it is worth considering. Thoughts? -- Noleander ( talk) 21:01, 20 March 2012 (UTC)
There is a web site [1] "About Pi. Ask Dr. Math FAQ" - it is used as a ref four times. It does not strike me as a reliable source. My intention, when I see refs like this, is to replace them with reliable secondary sources listed in the new References section. I don't see any material yet that should be outright deleted, but the sourcing is relying too much on primary sources. So, I don't foresee too many changes: just replacing a few cites; consolidating some material; improving the prose a little bit. -- Noleander ( talk) 20:04, 17 March 2012 (UTC)
The FA criteria suggest that an ideal article should not have a "see also" section, on the theory that a truly comprehensive article's body would mention (& have a link to) any related article. This article has about 5 articles in the See also section, including the Indiana pi bill (and it is also mentioned in the Approximations of π subarticle). I suggest adding a very brief mention of that article somewhere in the article .. perhaps in some "crackpot" paragraph about continued attempts to square the circle after 1882. Personally, I have no objection to See Also sections in FA articles, but moving such articles into the body is a desirable goal. -- Noleander ( talk) 20:35, 17 March 2012 (UTC)
I just stumbled on this citation: [2] which is used three times in the article. I propose to replace it with a more reliable source. -- Noleander ( talk) 16:31, 20 March 2012 (UTC)
Under Estimating the value it says (under the greyed "image" to the right) "A calculation of π accurate to 1120 decimal digits was obtained using a gear-driven calculator in 1948, by John Wrench and Levi Smith. This was the most accurate calculation of π before electronic computers came into use." while under Infinite series it says (last paragraph) "Infinite series based on the arctan function generally converge much faster than other infinite series, and were used to set records for the next 300 years, culminating in a 620 digit approximation in 1946 by Daniel Ferguson – the best approximation calculated without the aid of an electronic computer."
At least one of those two statements must be false - or?
Also
Chronology of computation of π says that in 1949 D. F. Ferguson and John Wrench (not John Wrench and Levi Smith in 1948) calculated π with 1120 decimals and the page on
John Wrench says that he and Levi Smith used a desk calculator to calculate π with 1160 decimals during 1945 to 1956. I.e. yet some more contradictions...
--
Episcophagus (
talk)
17:33, 26 March 2012 (UTC)
The article has a few sections whose charters are a bit fuzzy:
I think the material is good, but the sections could be cleaner if they were reorganized as follows:
I'm not proposing to remove any material, simply to clarify the charters of the sections and move things around a bit to better track the secondary sources. Thoughts? -- Noleander ( talk) 10:33, 22 March 2012 (UTC)
The Pi#Probability and statistics section contains a couple of paragraphs on pi and Buffon's needle. The context of that section is showing how pi appears (usually unexpectedly) in various scientific disciplines .... the example (in that section) of pi in gauss normal distribution is a great example. But Buffon's needle problem is circular/trigonometric in nature, and pi is expected there. So, I think Buffon's needle is better treated (in this article) as a monte carlo approach to estimating pi. So perhaps the Buffon's needle material should be split out into a new section "Monte Carlo estimations". That new section could also include the dart board approach to calculating pi (which is described in Approximations_of_π#Summing_a_circle.27s_area, but is not yet in the pi article). Thoughts? -- Noleander ( talk) 11:40, 22 March 2012 (UTC)
The picture of a rolling wheel at the top of the article is really, really good. Probably worth more than a thousand words. But, there is also the convention that sidebar navboxes, if present in an article, are placed in the upper right corner of the article. So, we should have a discussion about whether the rolling wheel should be above or below the sidebar navbox. When this article achieved GA status in 2007, the rolling wheel was at the top, but that was before the sidebar navbox was introduced in May 2010. There is an archived Talk page discussion on which should be on top, from May 2011, but it was inconclusive. Personally, either way seems okay; I can see arguments both ways. But I am planning on nominating this for FA status soon, so we should probably have the discussion and get consensus one way or another. -- Noleander ( talk) 14:55, 4 April 2012 (UTC)
The Definitions section currently has 5 sample definitions based on trig:
Most sources that mention this kind of definition only cite 1, 2 or 3 examples. I'm wondering if having 5 would give readers the wrong impression that these are critical, and all five are significant somehow? Maybe trim down to 2 or 3? -- Noleander ( talk) 03:38, 7 April 2012 (UTC)
The section titled "Geomorphology and chaos theory" seems a bit fishy to me. First, it says " Albert Einstein was the first to suggest that rivers have a tendency towards an ever more loopy path because the slightest curve will lead to faster currents on the outer side ..." which I find hard to believe. Second, the word "chaos" does not appear in the text of the section, so why is it in the title? I'll do some research and make sure the material reflects the sources, but if anyone has some thoughts, please speak up. -- Noleander ( talk) 03:25, 4 April 2012 (UTC)
The "Properties" section contains the following sentence:
I read the source, but it doesn't seem to warrant inclusion in this article. The way I read it is the authors have some ideas, but they have not proven anything yet. There must be hundreds of "plausible conjectures" about pi, but we cannot include them all in this article. Unless some strong secondary sources mention this conjecture, I suggest removing it. Thoughts? -- Noleander ( talk) 17:54, 4 April 2012 (UTC)
The subsections of "In mathematics and science" use a variety of approaches to text formatting: the Number Theory, Geometry and trigonometry, and River sections use a simple prose paragraph. The Physics and Probability sections use a bulleted technique. The Complex numbers and calculus sections are non-bulleted, but list-like. I think the big question is: Should the sections use bullets? or avoid bullets? The MOS says "Do not use lists if a passage is read easily as plain paragraphs." I believe that the Featured Article reviewers, in general, view bullets unfavorably. Looking at the text in question, I see no harm in removing the bullets. One upside is that it will induce editors to add textual background & explanation of the formulae, and thus make it more informative to lay readers. Thoughts? -- Noleander ( talk) 14:12, 5 April 2012 (UTC)
The following sentence in the Name section either says the same thing twice (that in English, we pronounce π as "pie") or erroneously says that Greeks also pronounce it this way: In English, π is pronounced as "pie" (/ˈpaɪ/), which is the same pronunciation used for the Greek letter. Joseph Lindenberg ( talk) 21:31, 9 April 2012 (UTC)
What I had read was that William Oughtred used π/δ to represent perimeter/diameter since π and δ are the Greek equivalents of p and d. I read this in the last paragraph of this article. He cites page 292 of Pi: A Source Book as his source. I also see it mentioned in the book The Joy of Pi. See the 5th page here. Joseph Lindenberg ( talk) 22:29, 9 April 2012 (UTC)
I'd like to hear other people's opinions on this, but I don't think magnetic permeability is a good example to use. The presence of π in it is entirely man-made and arbitrary. Scientists set the size of SI units to produce that result. (It was done so that the 4π would cancel out the 4π in formulas like the Biot-Savart Law.) They could just as easily have set the size of their units to make equal their favorite lottery number. You'll notice that none of the other physics formulas listed have units attached. Using the Biot-Savart Law instead would just seem more intellectually honest. (Ultimately though, the 4π in it and in Coulomb's law come from the 4π in the surface area of a sphere.) Joseph Lindenberg ( talk) 02:09, 10 April 2012 (UTC)
I'm still planning on nominating the article for FA status. There are a few tasks remaining, such as ensuring that all citations are uniformly formatted; validating all citations to make sure they support the material in the article; and reviewing the lead to make sure it is a good summary of the entire article. After that, I'll open up a peer review request and then, if the PR outcome is good, nominate for FA. If any editor has suggestions or ideas for improvement, please speak up! -- Noleander ( talk) 16:59, 10 April 2012 (UTC)
An editor removed material on pyramids & the meandering river. I restored the pyramid material, because it is discussed in many reliable secondary sources on pi. Perhaps that text could be improved to make it clearer that most modern scientists/egyptologists don't think that pi was involved in the pyramid shapes, but total removal is a bit much. The meandering river material is not as widely discussed by 2ndary sources, although it is in the Posamentier source. So that is less clear case for inclusion ... although it is a great example of unusual places in the sciences where pi pops up, which is the point of that section. Thoughts? -- Noleander ( talk) 19:52, 10 April 2012 (UTC)
There is a rather famous paradox involving pi: if a rope is wrapped tightly around the equator; then lengthened by 10 meters; then made into a perfect circular shape and lifted above the earth's surface (but still centered on the earth's center): How high is the rope above the earth's surface. Most people expect a small value, like a few millimeters, but the answer is nearly 2 meters. I realize this is rather trivial puzzle, and the article should not be a collection of brain teasers, but I've seen this particular paradox in many, many sources, and it seems like something that would be informative to a lay reader. Thoughts? -- Noleander ( talk) 16:37, 11 April 2012 (UTC)
The article feels overcrowded with images, especially images of mathematicians. I think that ultimately the images should be thinned, starting with those of mathematicians. The images of mathematicians really don't provide any additional detail that is useful in understanding the article. Although sometimes such images can provide visual cues for some readers, they are probably counterproductive in an article already rich with (mathematical) imagery. Sławomir Biały ( talk) 12:15, 18 April 2012 (UTC)
An editor recently added the sentence " In some fonts though, a lower-case π lacks curves and looks very similar to a capital Π. " in to the name section. I'm not sure if it belongs there: it seems rather obscure ... I've removed it temporarily, so we can discuss here and figure out the best way to proceed. I think the editor was motivated (as indicated in edit history comment) by the fact that some of the diagrams in the article use a font for pi that looks straight-line-ish, almost like a capital PI. The editor, correctly, was concerned that readers may get confused by seeing the curvy pi in the text; yet the straight-line pi in some diagrams. One solution would be to fix the diagrams to use a curvier pi font. Another would be to insert a sentence like " In some fonts though, a lower-case π lacks curves and looks very similar to a capital Π. " Another would be to do nothing. Thoughts? -- Noleander ( talk) 13:12, 18 April 2012 (UTC)
I gave it a try. Have a look, feel free to revert if you disagree. Nageh ( talk) 10:59, 19 April 2012 (UTC)
A peer review was done by user User:RJH at Wikipedia:Peer review/Pi/archive2. User User:Jakob.scholbach has volunteered to do an additional review, which is great. After that second review is done, the article should be ready to go to FAC. Thanks to all editors that have helped by making improvement to the article, often correcting my infelicitous wording. -- Noleander ( talk) 14:20, 15 April 2012 (UTC)
We've had two great editors provide input at the peer review so far. A third editor, User:Jakob.scholbach, has said they will provide more input some time this week. My plan is to resolve the issues raised by the 3rd reviewer; then make one final pass thru the article for prose quality; then take it to FAC; probably in May. -- Noleander ( talk) 13:15, 18 April 2012 (UTC)
In regards to my comment on the Approximations section in the PR, maybe it would help to rename it to Other approximations or Other approximation methods. That could make it more clear why some of the approximation methods are actually being discussed in the History section. Nageh ( talk) 15:18, 21 April 2012 (UTC)
Generally, I think it is better to avoid starting sentences with symbols whenever possible, chiefly since it becomes impossible to capitalize the first letter of a sentence, and interferes with reading in other ways (paragraph breaks, etc.) Many of the sentences in the article, especially those of the lead, do start with the symbol π. It might be worth thinking about how to rephrase these to avoid doing that. Sławomir Biały ( talk) 20:12, 23 April 2012 (UTC)
Wow, that's weird. This diff shows that a comma was changed to a period. Yet, in the source text there is a still a comma. Anyone else seeing this? Nageh ( talk) 18:57, 24 April 2012 (UTC)
I've initiated a discussion at the Tau Talk page suggesting that the tau article be restored. I also believe that a brief mention of tau in this article is okay. If anyone wants to discuss restoring the tau article, please contribute at the tau Talk page (rather than here) to keep the discussion co-located. -- Noleander ( talk) 14:01, 28 April 2012 (UTC)
The article says that infinite series are "sums or products of an infinite number of terms". It also, for example, calls the Wallis product an infinite series. I'm not used to that definition of series (infinite or not). I thought a series always meant a sum. -- Joseph Lindenberg ( talk) 02:10, 28 April 2012 (UTC)
I've re-worded the "Infinite Series" section so this potential confusion is no longer an issue. Of course, editors are free to continue discussing terminology! -- Noleander ( talk) 14:13, 28 April 2012 (UTC)
I'm really sorry Noleander, but I still don't think these two are correct.
"The first infinite sequence discovered in Europe was an infinite product (rather than an infinite sum"
"The second infinite series found in Europe, by John Wallis in 1655, also was an infinite product."
What do you guys think? Am I being overly picky? It is a mathematics article, though. -- Joseph Lindenberg ( talk) 21:13, 28 April 2012 (UTC)
Noleander, it looks like you could use the term infinite expression to mean something that could be either an infinite series (which by definition involves summation, not multiplication) or an infinite product. Take a look at the Wikipedia article on it. -- Joseph Lindenberg ( talk) 22:46, 28 April 2012 (UTC)
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Archive 5 | ← | Archive 7 | Archive 8 | Archive 9 | Archive 10 | Archive 11 | → | Archive 15 |
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Add
in the section under
"See also"
LynneMD80 ( talk) 01:55, 6 June 2011 (UTC)
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Yazzcoat (
talk)
11:50, 12 June 2011 (UTC)
ARITHMETIC PII
Surround rooms, living rooms witch is circle, what have bossebility know square meter. 6 meter long diameter 6x 2 × pii = m2 12 x 3,14 = 37,68m2.
8 meter long, diameter = 8 multiplication 2 x pii ( 8x 2 x 3,14) = m2.
10,000 Colors of Pi
Suggest addition of this link:
http://www.donnelly-house.net/funcrec/picolors/ — Preceding unsigned comment added by 24.10.49.212 ( talk) 22:34, 6 July 2011 (UTC)
suggestion, adding that the first 3 digits of pi, when looked at in a mirror, resemble the English word pie. — Preceding
unsigned comment added by
75.104.47.201 (
talk)
20:13, 22 July 2011 (UTC)
I've removed the claim that pi appears in formulas that have no relationship to Euclidean geometry. It was incorrectly cited, but I think more importantly, it's misleading. All the formulas we give as examples _are_ related to Euclidean geometry in the sense that they use pi to calculate density functions (abstracted from geometry), or to enable translations between linear and radial measurements. My concern is that we are suggesting that pi is a _physical_ constant, which arguably it isn't. Perhaps this distinction should be clarified more in the text? But from the list of examples, it is clear that pi gets used in a diverse range of places. Ethan Mitchell ( talk) 20:37, 6 August 2011 (UTC)
In his book The Riddle of the Pyramids, physicist Kurt Mendelssohn notes the relations to pi in the measurements of the Pyramids. He proposes that since we know the Egyptians did not achieve the value of pi until much later than the building of the pyramids, that the relationships most likely originate in pragmatic building techniques. He notes that the Egyptians couldn't have used ropes to measure long distances, because they stretch, and that a good solution is to count the number of revolutions of wooden drum. If you make the diameter of the drum, for example, one cubit, and then make the base the same number of "rolled" cubits as you make the height in "regular" cubits, then the relationship to pi emerges by itself, as a consequence of the tools used. You can find the reference in Chapter Three of Mendelssohn's book, "The Unsolved Problems." In my paperback edition (Cardinal, 1976, from the 1974 Thames & Hudson edition), the discussion is on PP76-79, where the proposal is sourced to electrical engineer T.E. Connolly. — Preceding unsigned comment added by Theonemacduff ( talk • contribs) 23:13, 23 August 2011 (UTC)
Can we please put the image File:Pi-unrolled-720.gif back in the lead, where it was when the article received GA status? I'm aware, of course that User:Anythingyouwant is, for whatever reason, opposed to this image. But it is the simplest and best picture illustrating the meaning of π, which is traditionally defined as the ratio of the circumference of a circle to its diameter. It does this without any equations, and so is accessible to the most naive reader. By contrast, the new lead images favored by User:Anythingyouwant both require equations of some form to understand, and so are going to be less accessible for a large number of potential readers (which is likely to include grade-school geometry students less comfortable with abstract equations). There has been consensus for this lead image in the past. I would like to put it back in. Let me know what you think. Sławomir Biały ( talk) 00:33, 17 September 2011 (UTC)
The images are somewhat better after recent edits, but I would still prefer (for reasons already articulated) to have the animation at the top. Sławomir Biały ( talk) 14:44, 17 September 2011 (UTC)
I agree that the "pi unrolled" animation is a good image, and it deserves to be part of the article. But I feel uneasy about having an animation right at the top of the page. I think the main focus of the lead should be the text, not moving pictures. Jowa fan ( talk) 03:42, 18 September 2011 (UTC)
What is the point of the infobox showing pi in multiple bases etc.? The best rational approximations are helpful, and I can sorta see the point of having binary and continued fractions, simply to show that there's no obvious pattern of the digits, but why octal, hexadecimal, and sexagesimal? They don't give any useful insight, and have no practical value. You might think the sexagesimal represention has some antiquarian value because of the Babylonian use of sexagesimal, but apparently the Babylonians didn't calculate with pi as a sexagesimal fraction (and certainly not to so many digits), but as the fraction 25/8 (not even 22/7). -- Macrakis ( talk) 14:37, 17 September 2011 (UTC)
Huh???? Sexagesimal is not notable, although it was used in Ptolemy's Almagest, but base-11 is notable because it appeared in some obscure novel?? I don't see any great need for so MANY digits in base-60 as what we saw there, but it's historically significant that base-60 was once standard in some eastern Mediterranean countries and was used in the most famous of all books ever written on astronomy. Michael Hardy ( talk) 02:18, 18 September 2011 (UTC)
Some time later this month it will become possible to write two archaic Greek letters in TeX in Wikipedia articles. Those two letters were used in Ptolemy's Almagest in the numeral system he used, with base 60 and subbase 10. So after that I will go check out his book from the library again, and do some further editing of the article about his table of chords. At that time, I will see exactly what he says about π, and probably say something about it in this article. Michael Hardy ( talk) 22:15, 18 September 2011 (UTC)
I like to say that first off Wikipedia is an encyclopedia, not a course in advanced astrophysics. Even so calculating Pi() to 40 digits would suffice in all possible uses in astrophysics. This page is deeply flawed in its emphasis. Pi critical function is in defining circular parameters and derivation of trigonometric phenomena. Pi, for instance, tells us the number of radians in a circle. E.g. (180/pi() = 1 radian in degrees). The radian is essential for the calculation of sines and cosines based on alpha, because it defines how many radians there are in a circle and because it makes if possible for us to relate angles in radians to angles commonly used in daily life (30, 45, 60, 90, 120, etc.). Several aspects of the mathematical usefulness of pi are virtually glossed over for this numerology which is nothing more than amateur science taken to an extreme. Most pages would place 80% of whats on this page into a paragraph "Pi in popular culture". This page is on the same caliber as the Apollo 16 page.
pi/2 = 90 (an arbitrary base 360' system in which is better based on the pi/radian based system) pi/3 = 60', in a right triangle the adjacent side is 1/2 the hypotenuse. pi/4 = 45', in a right triangle both the opposite and adjacent sides are equal, and the length is 1/(2^0.5) the hypotenuse pi/6 = 30', in a right triangle the opposite side = 1/2 the hypotenuse.
This page is an excellent example of the fact that mathematics is not a pure science, but a representative language-tool for science. Pi() has scientific meaning in that its properties supercede base-systems. But knowing the digital representation in base 10 is therefore meaningless, even less meaningful in the age of computers when its precision is arbitrarily set to 8, 16, 32, or 64 digits and can be implemented without any knowledge using terms like pi(). Memorizing 100,000 digits is even more meaningless. These numerologistic analysis are the equivelant of a page on supercalifragilisticexpialidosious. PB666 yap 22:13, 14 October 2011 (UTC)
Just saw that another calculation has it to 10 trillion digits. http://www.numberworld.org/misc_runs/pi-10t/details.html — Preceding unsigned comment added by 67.169.191.53 ( talk) 03:46, 20 October 2011 (UTC)
Yeah, by the same guys:
Ricardobeat ( talk) 18:39, 22 October 2011 (UTC)
It should be on the left or on the right, but not both sides, eh? 68.2.46.143 ( talk) 20:21, 11 November 2011 (UTC)
I've inserted a slightly modified top image. I made it myself, so the quality isn't so good. But, I've submitted a request to the image gurus to fix it up. Anythingyouwant ( talk) 19:27, 18 September 2011 (UTC)
I like this image a lot. — Preceding unsigned comment added by 173.66.156.8 ( talk) 15:19, 13 November 2011 (UTC)
I saw that the 50 decimal representation of π I added to the lead section was removed. I think it should be there, and I reason like this:
Many times when people visit this article, it is only to get an accurate numerical value of π, why it is important that the value is easy to find. Therefore, it should be in the lead section of the article, or at least somewhere close to it so it can be seen immediately when the article is loaded. For example, I usually use Wikipedia to look up both physical and mathematical constants when I need them for either programming or for calculations. In those cases, I don't want to have to look through a large part of the article in order to find the numerical value, and for π, 3.14 is simply not enough. — Kri ( talk) 01:09, 16 November 2011 (UTC)
Yes, "its decimal representation never ends or repeats indefinitely" is vague compared to a longer explanation like "... repeats infinitely like 5/6=0.8333333 ... or 3/22=0.13636363636 ...". But "repeats indefinitely" is less vague than just "repeats", which is simply wrong; the decimal representation does repeat finitely. Art LaPella ( talk) 06:35, 10 October 2011 (UTC)
There's recently been an edit war regarding the content of Pi#Alternative_notation. My feeling is that we already have an article for Tau (2π), so there's no need to repeat too much of that content here. I'm concerned that appears in the current version reads like an advertisement for the use of tau: it gives undue weight to this notation. I'd prefer to see this section cut right back: people can go to the main article if they want to learn more. Jowa fan ( talk) 03:21, 17 November 2011 (UTC)
I replaced the summary with new text which explains the rationale under the introduction of the new constant. (The question "why" pops up immediately and naturally.) Max Longint ( talk) 02:18, 18 November 2011 (UTC)
Nobody posted any objections, so I have changed the section title to "Tau as an alternative circle constant". I will monitor this Talk page for the next few days, so please post any new objections here instead of just reverting my edit. I'll be sure to respond promptly. And I'm still eager to hear any thoughts you have on whether tau is the best circle constant, versus whether pi or tau is better everywhere else. Thanks. Joseph Lindenberg ( talk) 22:40, 18 November 2011 (UTC)
The history section of this article claims a source, which makes an inaccurate assumption from the Bronze Sea description in 1Kings 7:23-26. The description in 1Kings includes that "the walls were sloped like a lily" showing taper.
If the bronze sea was vertically walled, pi=3 would stand, but it's approximately a frustum of a cone. A simple description is shown at the following link: http://www.yihyeh.com/the-bronze-sea.html
Since the value of a bath is known, and the number of baths that the bronze sea held is known, determining the volume provides a great estimate of the value of a biblical cubit. The key is that the simplest number of measurements is given, as expected when manufacturing screws or any crude form that was tapered. No938 ( talk) 04:16, 27 November 2011 (UTC)
In the article it says:
When used as a symbol for the mathematical constant, the Greek letter (π) is not capitalized at the beginning of a sentence. The capital letter Π (Pi) has a completely different mathematical meaning; it is used for expressing the product of a sequence.
Yet in the article, the capital 'Π' instead of 'π' is used consistently at the start of sentences. Do we not contradict ourselves? Is there a problem with {{pi}}? Kleuske ( talk) 09:16, 10 December 2011 (UTC)
As far as I can tell, this hasn't been discussed recently, but I thought use of {{ frac}}, such as in the section Pi#Estimating the value, is discouraged in mathematical articles, per WP:MOSMATH. — Arthur Rubin (talk) 16:07, 10 December 2011 (UTC)
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hi i want to edit this wiki page as i have the first 100,000 didgets of pi in a txt document which i can put a link to on my current website http://skweekz.sexyi.am/upload/PI.txt
thanks for reading
p.s i would be happier if you would to deny this and edit the page yourself if thats no problem.
best regards richard aka skweekz
Skweekz ( talk) 14:10, 21 December 2011 (UTC)
I've added a hatnote to deal with capital Pi. Frankly, the lack of a hatnote to this effect was disgraceful... many readers of Wikipedia have not completed high school mathematics, and might be looking for this meaning; Most probably have, and would laugh at the current redirect even now we explain it.
See also Template talk:Hatnote templates documentation#Is there a suitable template for this. Andrewa ( talk) 19:41, 5 December 2011 (UTC)
Unfortunately that π and Π link to the same page is unavoidable as WP ignores the capitalisation of the initial letter. The question of which page belongs at π is a different one, and depends on which if anything is the primary topic for pi and π. One thing we can look at for this is pageview statistics:
The current page is overwhelmingly the article sought by users reaching here: few visit the disambiguation page after, and under 1% use the redirect Π to get here. So the current page is the primary topic and there is very little evidence readers are looking for another topic instead of the one here.-- JohnBlackburne words deeds 20:24, 6 December 2011 (UTC)
The pi value was given by the Indian mathematician ARYABHATA. — Preceding
unsigned comment added by
S.R.Aniruddha (
talk •
contribs)
17:00, 1 January 2012 (UTC)
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Typo for the caption under the digits of pi: "An calculation" should be "A calculation".
Deadwisdom ( talk) 22:07, 21 December 2011 (UTC)
On article there is equation for calculation of individual digits. I'm not sure about this because none of terms in sum has finite decimal representation, and I think hexadecimal representations are also infinite. So I think that to find digit N we must find Nth digit in first term, Nth digit in second term,...,Nth digit in (N-1)th term, and remainders from further digits. Because of this I think this method isn't to effective, but one simpler ones. This is rather question about mistake in my thinking, not any proof Wojowu ( talk) 17:32, 3 January 2012 (UTC)
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I was going to type that computers are still trying to get a non repeating number
Jcarcerano ( talk) 03:22, 7 January 2012 (UTC)
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Please add a link for "Ramanujan" (a mathematician who is mentioned in this article): there is a wikipedia page for him. http://en.wikipedia.org/wiki/Srinivasa_Ramanujan Eternal fizzer ( talk) 12:24, 20 January 2012 (UTC)
In the paragraph that starts, "In 1706 John Machin was the first ...", I find it perplexing that Machin attempts to compute π based on 4atan(1/5)-atan(1/239) when π/4 = atan(1). Surely, if he were sophisticated to do what is said, he should have known of the simpler formula. Ksn ( talk) 16:07, 15 February 2012 (UTC)
I'm planning on working on the article, with the ultimate goal of reaching WP:FA status. I've gotten a few books from the library, including π: A biography of the world's most mysterious number (by Posametier & Lehmann); and Pi Unleashed (by Arndt and Haenel). The article is already in decent shape (and is already GA status), with some great illustrations. The biggest jobs appear to be (1) ensuring that all material has a good source, per WP:V; and (2) ensuring that the article is comprehensive. Plus, making sure the prose is professional quality (not my strong suit). Any help, suggestions, sources, etc. would be appreciated. -- Noleander ( talk) 21:08, 8 March 2012 (UTC)
Well,it's because of the first 3 digits of π,3.14,it tell us that it's on 3/14 which is March 14. — Preceding unsigned comment added by 207.237.10.60 ( talk) 23:38, 14 March 2012 (UTC)
The first 1120 of Pi are:3.14159265358979323846264338327950288419716939937510582097494459230781640628620899862803482534211706798214808651328230664709384460955058223172535940812848111745028410270193 8521105559644622948954930381964428810975665933446128475648233786783165271201909145648566923460348610454326648213393607260249141273724587006606315588174881520920962829254091715 3643678925903600113305305488204665213841469519415116094330572703657595919530921861173819326117931051185480744623799627495673518857527248912279381830119491298336733624406566430 8602139494639522473719070217986094370277053921717629317675238467481846766940513200056812714526356082778577134275778960917363717872146844090122495343014654958537105079227968925 8923542019956112129021960864034418159813629774771309960518707211349999998372978049951059737328160963859502445945534690830264252230825334468503526193118817101000313783875288658 7533208381420617177669147303598253490428755468731159562863882353787593751957781857780532171226806613001927876611195909216420198938095257201065485863278865936153381827968230301 9520353018529689957736225994138912497217752834791315155748572424541506959 — Preceding unsigned comment added by 207.237.10.60 ( talk) 23:48, 14 March 2012 (UTC)
THis image was working before http://en.wikipedia.org/wiki/File:Pi-unrolled-720.gif Now it isn't. Is this a local problem? Picklebobdogflog ( talk) 00:18, 16 March 2012 (UTC)
For a mathematical constant as thoroughly studied as π, the section on renaming it to τ should not be here. It is a gross violation of WP:WEIGHT. Moreover, none of the sources referenced meet even the most minimal standards of scholarship needed for inclusion in an encyclopedia article. The symbol τ is not used in any mainstream mathematical sources. Sławomir Biały ( talk) 11:00, 19 March 2012 (UTC)
The two subsections " Representation as a continued fraction" and "Memorizing digits" are currently under the "History" top level section, which is not appropriate. I'll move them out to be top level sections for now, but that is not ideal, since that would lead to a lot of top level sections. This article may need a "Miscellaneous" top level section, to hold "Tau", "In Popular Culture", "Representation as a continued fraction" and "Memorizing digits" ... but "Misc" is not ideal either. Any thoughts? -- Noleander ( talk) 19:32, 17 March 2012 (UTC)
The History section has an Antiquity subsection; but before that is an intro paragraph about Egypt. Clearly, that Egypt material belongs in the Antiq section, so I'll move it.
There seem to be several "obvious" changes to make, similar to that, so I'll forge ahead without notifications here on the Talk page. If anyone sees a mistake, or does not agree with a particular change, feel free to revert. Or, better yet, just drop a quick note here on the Talk page and I'll remedy any issues. -- Noleander ( talk) 19:42, 17 March 2012 (UTC)
The pyramids section seems a bit verbose; and also a bit polemic, emphasizing the "they were based on pi" viewpoint. I suggest tightening that section a bit, and also relying more on secondary sources. I think the tone should be something like "Some egyptologists have speculated ..., but others view the proposal with skepticism ...". Thoughts? -- Noleander ( talk) 19:59, 17 March 2012 (UTC)
The Pi#Computer_era section has a large table of about 20 infinite sum equations for pi. This seems excessive. This article is a main article, with several subarticles. The kind of detail in that table should be moved down into a subarticle such as Approximations_of_π or List of formulae involving π. Of course, a few key formulae (from that table) could be left in this article if secondary sources specifically mention them prominently. Thoughts? -- Noleander ( talk) 14:51, 19 March 2012 (UTC)
When displaying incidental formulae, the article has the choice of placing them in between paragraphs (inline), or in a sidebar box. I have no preference one way or another, but as an experiment, I've placed a few on the side in the Pi#Infinite_series section. The convention in WP math articles seems to favor centering the formulae in-line. For instance the Logarithm article, a FA article within the Math project puts all its formulae inline. If anyone objects to this temporary formatting experiment, I can move them back in-line, no problem. At some point, before this is nominated for FA status, we'll have to decide on way or another. As I say, I have no preference on way or another, but it is worth considering. Thoughts? -- Noleander ( talk) 21:01, 20 March 2012 (UTC)
There is a web site [1] "About Pi. Ask Dr. Math FAQ" - it is used as a ref four times. It does not strike me as a reliable source. My intention, when I see refs like this, is to replace them with reliable secondary sources listed in the new References section. I don't see any material yet that should be outright deleted, but the sourcing is relying too much on primary sources. So, I don't foresee too many changes: just replacing a few cites; consolidating some material; improving the prose a little bit. -- Noleander ( talk) 20:04, 17 March 2012 (UTC)
The FA criteria suggest that an ideal article should not have a "see also" section, on the theory that a truly comprehensive article's body would mention (& have a link to) any related article. This article has about 5 articles in the See also section, including the Indiana pi bill (and it is also mentioned in the Approximations of π subarticle). I suggest adding a very brief mention of that article somewhere in the article .. perhaps in some "crackpot" paragraph about continued attempts to square the circle after 1882. Personally, I have no objection to See Also sections in FA articles, but moving such articles into the body is a desirable goal. -- Noleander ( talk) 20:35, 17 March 2012 (UTC)
I just stumbled on this citation: [2] which is used three times in the article. I propose to replace it with a more reliable source. -- Noleander ( talk) 16:31, 20 March 2012 (UTC)
Under Estimating the value it says (under the greyed "image" to the right) "A calculation of π accurate to 1120 decimal digits was obtained using a gear-driven calculator in 1948, by John Wrench and Levi Smith. This was the most accurate calculation of π before electronic computers came into use." while under Infinite series it says (last paragraph) "Infinite series based on the arctan function generally converge much faster than other infinite series, and were used to set records for the next 300 years, culminating in a 620 digit approximation in 1946 by Daniel Ferguson – the best approximation calculated without the aid of an electronic computer."
At least one of those two statements must be false - or?
Also
Chronology of computation of π says that in 1949 D. F. Ferguson and John Wrench (not John Wrench and Levi Smith in 1948) calculated π with 1120 decimals and the page on
John Wrench says that he and Levi Smith used a desk calculator to calculate π with 1160 decimals during 1945 to 1956. I.e. yet some more contradictions...
--
Episcophagus (
talk)
17:33, 26 March 2012 (UTC)
The article has a few sections whose charters are a bit fuzzy:
I think the material is good, but the sections could be cleaner if they were reorganized as follows:
I'm not proposing to remove any material, simply to clarify the charters of the sections and move things around a bit to better track the secondary sources. Thoughts? -- Noleander ( talk) 10:33, 22 March 2012 (UTC)
The Pi#Probability and statistics section contains a couple of paragraphs on pi and Buffon's needle. The context of that section is showing how pi appears (usually unexpectedly) in various scientific disciplines .... the example (in that section) of pi in gauss normal distribution is a great example. But Buffon's needle problem is circular/trigonometric in nature, and pi is expected there. So, I think Buffon's needle is better treated (in this article) as a monte carlo approach to estimating pi. So perhaps the Buffon's needle material should be split out into a new section "Monte Carlo estimations". That new section could also include the dart board approach to calculating pi (which is described in Approximations_of_π#Summing_a_circle.27s_area, but is not yet in the pi article). Thoughts? -- Noleander ( talk) 11:40, 22 March 2012 (UTC)
The picture of a rolling wheel at the top of the article is really, really good. Probably worth more than a thousand words. But, there is also the convention that sidebar navboxes, if present in an article, are placed in the upper right corner of the article. So, we should have a discussion about whether the rolling wheel should be above or below the sidebar navbox. When this article achieved GA status in 2007, the rolling wheel was at the top, but that was before the sidebar navbox was introduced in May 2010. There is an archived Talk page discussion on which should be on top, from May 2011, but it was inconclusive. Personally, either way seems okay; I can see arguments both ways. But I am planning on nominating this for FA status soon, so we should probably have the discussion and get consensus one way or another. -- Noleander ( talk) 14:55, 4 April 2012 (UTC)
The Definitions section currently has 5 sample definitions based on trig:
Most sources that mention this kind of definition only cite 1, 2 or 3 examples. I'm wondering if having 5 would give readers the wrong impression that these are critical, and all five are significant somehow? Maybe trim down to 2 or 3? -- Noleander ( talk) 03:38, 7 April 2012 (UTC)
The section titled "Geomorphology and chaos theory" seems a bit fishy to me. First, it says " Albert Einstein was the first to suggest that rivers have a tendency towards an ever more loopy path because the slightest curve will lead to faster currents on the outer side ..." which I find hard to believe. Second, the word "chaos" does not appear in the text of the section, so why is it in the title? I'll do some research and make sure the material reflects the sources, but if anyone has some thoughts, please speak up. -- Noleander ( talk) 03:25, 4 April 2012 (UTC)
The "Properties" section contains the following sentence:
I read the source, but it doesn't seem to warrant inclusion in this article. The way I read it is the authors have some ideas, but they have not proven anything yet. There must be hundreds of "plausible conjectures" about pi, but we cannot include them all in this article. Unless some strong secondary sources mention this conjecture, I suggest removing it. Thoughts? -- Noleander ( talk) 17:54, 4 April 2012 (UTC)
The subsections of "In mathematics and science" use a variety of approaches to text formatting: the Number Theory, Geometry and trigonometry, and River sections use a simple prose paragraph. The Physics and Probability sections use a bulleted technique. The Complex numbers and calculus sections are non-bulleted, but list-like. I think the big question is: Should the sections use bullets? or avoid bullets? The MOS says "Do not use lists if a passage is read easily as plain paragraphs." I believe that the Featured Article reviewers, in general, view bullets unfavorably. Looking at the text in question, I see no harm in removing the bullets. One upside is that it will induce editors to add textual background & explanation of the formulae, and thus make it more informative to lay readers. Thoughts? -- Noleander ( talk) 14:12, 5 April 2012 (UTC)
The following sentence in the Name section either says the same thing twice (that in English, we pronounce π as "pie") or erroneously says that Greeks also pronounce it this way: In English, π is pronounced as "pie" (/ˈpaɪ/), which is the same pronunciation used for the Greek letter. Joseph Lindenberg ( talk) 21:31, 9 April 2012 (UTC)
What I had read was that William Oughtred used π/δ to represent perimeter/diameter since π and δ are the Greek equivalents of p and d. I read this in the last paragraph of this article. He cites page 292 of Pi: A Source Book as his source. I also see it mentioned in the book The Joy of Pi. See the 5th page here. Joseph Lindenberg ( talk) 22:29, 9 April 2012 (UTC)
I'd like to hear other people's opinions on this, but I don't think magnetic permeability is a good example to use. The presence of π in it is entirely man-made and arbitrary. Scientists set the size of SI units to produce that result. (It was done so that the 4π would cancel out the 4π in formulas like the Biot-Savart Law.) They could just as easily have set the size of their units to make equal their favorite lottery number. You'll notice that none of the other physics formulas listed have units attached. Using the Biot-Savart Law instead would just seem more intellectually honest. (Ultimately though, the 4π in it and in Coulomb's law come from the 4π in the surface area of a sphere.) Joseph Lindenberg ( talk) 02:09, 10 April 2012 (UTC)
I'm still planning on nominating the article for FA status. There are a few tasks remaining, such as ensuring that all citations are uniformly formatted; validating all citations to make sure they support the material in the article; and reviewing the lead to make sure it is a good summary of the entire article. After that, I'll open up a peer review request and then, if the PR outcome is good, nominate for FA. If any editor has suggestions or ideas for improvement, please speak up! -- Noleander ( talk) 16:59, 10 April 2012 (UTC)
An editor removed material on pyramids & the meandering river. I restored the pyramid material, because it is discussed in many reliable secondary sources on pi. Perhaps that text could be improved to make it clearer that most modern scientists/egyptologists don't think that pi was involved in the pyramid shapes, but total removal is a bit much. The meandering river material is not as widely discussed by 2ndary sources, although it is in the Posamentier source. So that is less clear case for inclusion ... although it is a great example of unusual places in the sciences where pi pops up, which is the point of that section. Thoughts? -- Noleander ( talk) 19:52, 10 April 2012 (UTC)
There is a rather famous paradox involving pi: if a rope is wrapped tightly around the equator; then lengthened by 10 meters; then made into a perfect circular shape and lifted above the earth's surface (but still centered on the earth's center): How high is the rope above the earth's surface. Most people expect a small value, like a few millimeters, but the answer is nearly 2 meters. I realize this is rather trivial puzzle, and the article should not be a collection of brain teasers, but I've seen this particular paradox in many, many sources, and it seems like something that would be informative to a lay reader. Thoughts? -- Noleander ( talk) 16:37, 11 April 2012 (UTC)
The article feels overcrowded with images, especially images of mathematicians. I think that ultimately the images should be thinned, starting with those of mathematicians. The images of mathematicians really don't provide any additional detail that is useful in understanding the article. Although sometimes such images can provide visual cues for some readers, they are probably counterproductive in an article already rich with (mathematical) imagery. Sławomir Biały ( talk) 12:15, 18 April 2012 (UTC)
An editor recently added the sentence " In some fonts though, a lower-case π lacks curves and looks very similar to a capital Π. " in to the name section. I'm not sure if it belongs there: it seems rather obscure ... I've removed it temporarily, so we can discuss here and figure out the best way to proceed. I think the editor was motivated (as indicated in edit history comment) by the fact that some of the diagrams in the article use a font for pi that looks straight-line-ish, almost like a capital PI. The editor, correctly, was concerned that readers may get confused by seeing the curvy pi in the text; yet the straight-line pi in some diagrams. One solution would be to fix the diagrams to use a curvier pi font. Another would be to insert a sentence like " In some fonts though, a lower-case π lacks curves and looks very similar to a capital Π. " Another would be to do nothing. Thoughts? -- Noleander ( talk) 13:12, 18 April 2012 (UTC)
I gave it a try. Have a look, feel free to revert if you disagree. Nageh ( talk) 10:59, 19 April 2012 (UTC)
A peer review was done by user User:RJH at Wikipedia:Peer review/Pi/archive2. User User:Jakob.scholbach has volunteered to do an additional review, which is great. After that second review is done, the article should be ready to go to FAC. Thanks to all editors that have helped by making improvement to the article, often correcting my infelicitous wording. -- Noleander ( talk) 14:20, 15 April 2012 (UTC)
We've had two great editors provide input at the peer review so far. A third editor, User:Jakob.scholbach, has said they will provide more input some time this week. My plan is to resolve the issues raised by the 3rd reviewer; then make one final pass thru the article for prose quality; then take it to FAC; probably in May. -- Noleander ( talk) 13:15, 18 April 2012 (UTC)
In regards to my comment on the Approximations section in the PR, maybe it would help to rename it to Other approximations or Other approximation methods. That could make it more clear why some of the approximation methods are actually being discussed in the History section. Nageh ( talk) 15:18, 21 April 2012 (UTC)
Generally, I think it is better to avoid starting sentences with symbols whenever possible, chiefly since it becomes impossible to capitalize the first letter of a sentence, and interferes with reading in other ways (paragraph breaks, etc.) Many of the sentences in the article, especially those of the lead, do start with the symbol π. It might be worth thinking about how to rephrase these to avoid doing that. Sławomir Biały ( talk) 20:12, 23 April 2012 (UTC)
Wow, that's weird. This diff shows that a comma was changed to a period. Yet, in the source text there is a still a comma. Anyone else seeing this? Nageh ( talk) 18:57, 24 April 2012 (UTC)
I've initiated a discussion at the Tau Talk page suggesting that the tau article be restored. I also believe that a brief mention of tau in this article is okay. If anyone wants to discuss restoring the tau article, please contribute at the tau Talk page (rather than here) to keep the discussion co-located. -- Noleander ( talk) 14:01, 28 April 2012 (UTC)
The article says that infinite series are "sums or products of an infinite number of terms". It also, for example, calls the Wallis product an infinite series. I'm not used to that definition of series (infinite or not). I thought a series always meant a sum. -- Joseph Lindenberg ( talk) 02:10, 28 April 2012 (UTC)
I've re-worded the "Infinite Series" section so this potential confusion is no longer an issue. Of course, editors are free to continue discussing terminology! -- Noleander ( talk) 14:13, 28 April 2012 (UTC)
I'm really sorry Noleander, but I still don't think these two are correct.
"The first infinite sequence discovered in Europe was an infinite product (rather than an infinite sum"
"The second infinite series found in Europe, by John Wallis in 1655, also was an infinite product."
What do you guys think? Am I being overly picky? It is a mathematics article, though. -- Joseph Lindenberg ( talk) 21:13, 28 April 2012 (UTC)
Noleander, it looks like you could use the term infinite expression to mean something that could be either an infinite series (which by definition involves summation, not multiplication) or an infinite product. Take a look at the Wikipedia article on it. -- Joseph Lindenberg ( talk) 22:46, 28 April 2012 (UTC)