Talk:Pi

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Update the last paragraph on Spigot Algorithms to reflect the computation of the 4x10^15th bit by Ed Karrels.(https://www.scu.edu/engineering/news/2012fall/pi.cfm), (http://www.karrels.org/pi/index.html) Yahoo computed the 2x10^15th bit using a cluster of 1000 machines; Ed Karrels' computation was done on one machine using CUDA.(http://en.wikipedia.org/wiki/CUDA) Oshkosher (talk) 15:35, 13 March 2013 (UTC)


New record as of December 28, 2013 - 12.1 Trillion Digits of Pi [1] -- Ninjamask (talk) 02:59, 17 February 2014 (UTC)


Tau[edit]

The pi/tau controversy makes an appearance at xkcd: "Pi vs. Tau". — Loadmaster (talk) 20:51, 12 December 2013 (UTC)

With respect to Tau=Pi/2 as proposed by Albert Eagle, the transformation of a unity length line to a two-dimensional semi-circular arc might serve as the defining example. Cerian Knight (talk) 18:41, 17 February 2014 (UTC)

Semi-protected edit request on 2 March 2014[edit]

Please change the following text: Two verses in the Hebrew Bible (written between the 8th and 3rd centuries BC) describe a ceremonial pool in the Temple of Solomon with a diameter of tencubits and a circumference of thirty cubits; the verses imply π is about three if the pool is circular.[25][26] Rabbi Nehemiah explained the discrepancy as being due to the thickness of the vessel. His early work of geometry, Mishnat ha-Middot, was written around 150 AD and takes the value of π to be three and one seventh.[27] See Approximations of π#Imputed biblical value.

To this: Two verses in the Hebrew Bible (written between the 8th and 3rd centuries BC) describe a ceremonial pool in the Temple of Solomon with a diameter of ten cubits and a circumference of thirty cubits; the verses imply π is about three if the pool is circular.[25][26] Rabbi Nehemiah explained the discrepancy as being due to the thickness of the vessel. His early work of geometry, Mishnat ha-Middot, was written around 150 AD and takes the value of π to be three and one seventh.[27] See Approximations of π#Imputed biblical value. Rabbi Eliyahu of Vilna (The Vilna Gaon) wrote in his commentary on the Bible that the correct reading of the Biblical text indicates to apply a factor of 111/106 which results in 1.04716981 to the approximate π value of 3. This means that the value of π used in the construction of the ceremonial pool was actually 1.04716981 X 3 which equals 3.14150943. It is accurate to the 4th decimal point. This factor is derived from the extraneous word "koh" (קוה) written in the original Hebrew of 1 Kings 7:23. It is to be pronounced however "ko" (קו). Similarly, in 2 Chronicles 4:2, the original Hebrew is actually written "ko" (קו). The Hebrew letters also have numerical values. (קוה) has a value of 111 and (קו) has a numerical value of 106. 108.2.9.169 (talk) 16:42, 2 March 2014 (UTC)

The edit as suggested is definitely unsatisfactory. The convoluted argument it is trying to describe can be seen a bit more clearly here[2] for example, but the editor's attempt doesn't get this over at all. In any event, the argument is ridiculous special-pleading. Actually I think it would be better to delete all but the first sentence of the quote above. In the Bible there is a description (in a bit about history, *not* mathematics) of a pool about 10 cubits in diameter and 30 cubits around. There is no problem whatsoever with that, because the value of pi is 3 to a first approximation. (If it said the pool was 6 cubits across and 43 cubits around, things would be different.) Imaginatorium (talk) 17:47, 2 March 2014 (UTC)
The international systems of units were not used in the time of King Solomon and it could create some conflicts because they were neither precise nor standard if it was used in today's measurements . I would still say three cubits for pi if I was living at that time.184.148.14.64 (talk) 02:17, 5 March 2014 (UTC)

Ludolphine number honourable mention?[edit]

With reference to Ludolph van Ceulen, "pi" was for a period of roughly 200 years often called the Ludolphine number&Ludolphsche Zahl, from his death in 1610 into the 19th century.

at present, the history section does not explicitly name this fairly important naming practice (to the extent that previous namings ARE important!), and a single sentence or so, for example along the line: "For about 200 years, pi was occasionally referred to as the Ludolphine number, in honour of Ludolph van Ceulen, who calculated pi correctly to 35 digits in the 16th century". Or something like that.Arildnordby (talk) 00:38, 15 March 2014 (UTC)

Ludolph is mentioned in Pi#Polygon_approximation_era. ~~ Ropata (talk) 13:01, 27 March 2014 (UTC)
Ok, that would be more than sufficient mentioning.Arildnordby (talk) 14:31, 27 March 2014 (UTC)

Edit Request[edit]

If under the section "Approximate Value" the first 100 decimal digits are defined as: 3.1415926535897932384626433832795028841971693993751058209749445923078164062862089986280348253421170679, then the leading 3 is not considered a decimal digit. In this case, under the section "Polygon approximation era", the sentence: "With a correct value for its seven first decimal digits, this value of 3.141592920... remained the most accurate approximation of π available for the next 800 years." should be replaced with "With a correct value for its six first decimal digits, this value of 3.141592920... remained the most accurate approximation of π available for the next 800 years." — Preceding unsigned comment added by 65.201.161.119 (talk) 15:31, 15 April 2014 (UTC)

I believe there is an issue here, but all this is modulo British/American terminology differences, which are often huge in these areas. In BrE (I was at school 1953-1966), the word for the digits after the decimal point is "decimal place", in which case this should be "six decimal places". But "digit" is a more general word, "decimal digit" is redundant, so I suggest this should be changed to "seven significant figures", which I think is universally correct. I will change it unless someone comes up with a problem. Imaginatorium (talk) 07:59, 23 April 2014 (UTC)
"Decimal digit" is redundant, because of "binary digit", "octal digit" and "hexadecimal digit" are commonly used. "Figure" is misleading: for many people "figure" is almost synonymous of "drawing". "Place" suffers for the lack of an accurate definition. "Digit" or "decimal digit" is the only word that is accurately defined, not only from a graphical point of view (a digit is a specific alphanumeric character), but also as a mathematical concept. The IP user is right, the digits before the dot must be counted. Otherwise, one would need to say that 3 and 2 are two approximations of π, both with zero correct digits. Thus, I disagree with Imaginatorium suggestion. Instead, I suggest to simply add "after the dot" after "100 decimal digits". D.Lazard (talk) 08:50, 23 April 2014 (UTC)

So my Question is. If you mirror Pi I mean if you take the digital Version of Pi and use the not operator. What kind of Number would you have then ? Also a transcendence Number ? What kind of Geometric Figure you can discern from this digit ? — Preceding unsigned comment added by 87.122.187.198 (talk) 20:59, 16 May 2014 (UTC)

So my Question is. If you take the digital Version of Pi and use the not Operator. What kind of Number would you have then? Also a transcendence Number ? What kind of Figure can you discern of this digit ? — Preceding unsigned comment added by 87.122.187.198 (talk) 21:03, 16 May 2014 (UTC)

So my Question is. If you take the digital Version of Pi and use the not Operator. What kind of Number would you have then. Also a transcendence Number ? What kind of Figure can you discern from this digit ? — Preceding unsigned comment added by 87.122.187.198 (talk) 21:06, 16 May 2014 (UTC)

Antiquity Section[edit]

Current entries in the antiquity India section give a feel that those calculators were off the mark where as Aryabhata and Madhava approximated Pi value to 5 and 11 digits accuracy. Infact, Aryabhata's work has been included in Polygon Approximation in a below section where it does not belong-I did not get any reference of his using a polygon method to calculate Pi value to 5 digit accuracy. I feel, Including Aryabhata and Madhava's works subsequently is also chronological otherwise, antiquity section itself is misleading?. Madhava's work gets a mention in Infinite series but does not stress on his value to pi value approximation. He was never in competition with any Persian mathematician. the language used does not sound neutral. Also, I feel, Wikipedia should revert all BC/AD to BCE and ACE. That can be another discussion. — Preceding unsigned comment added by Sudhee26 (talkcontribs) 21:44, 9 June 2014 (UTC)

I'm puzzled by your apparent claim that the mentioning of Aryabhata and Madhava is not chronological, although perhaps I misunderstand your intended meaning. These do not belong in the "antiquity" section because they do not predate the influence of Greek mathematics. The cited source suggests that the origin of Aryabhata's figure is possibly from Archimedes, having made its way into India. Although it goes on to explain how Aryabhata might have obtained it independently by a polygonal approximation. The material that you added to the article on Madhava was totally out of place in the "Antiquity" section, and duplicated content already in the article. I don't think the article underplays the importance of Madhava, however I do agree that the last sentence of that paragraph is somewhat problematic. (The issue of BC versus BCE is discussed at WP:MOSDATE. It is not considered appropriate to change from one style to another.) Sławomir Biały (talk) 22:38, 9 June 2014 (UTC)