Talk:Pi

Tau

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)

how to compute with fractions

Divide numbers (whole number,irrational or rational )below 180 by 180 or digits in the middle of 180 and 360 or 360 and 540 all multiple of 180 ,and take sin of the result in radian mode or by the use of Taylor series then change it to degree mode and take the inverte sin from the resutlt in radian mode and you obtain digits of pi by choosing the number that was divided by 180 or 360 and 540....etc. example of a fraction 355/113(a fraction from the article). 355/360=0.98611111111111111111111111111111..... in radian=0.83388586828323059431360578387878.... in degree=56.500004797622844197953735997243....*2(because 360 is a multiple of 180)=113.00000959524568839590747199449... therefore 355/113=3.141592........

355/113.00000959524568839590747199449...=pi

70.55.23.230 (talk) 19:18, 27 January 2014 (UTC)

Semi-protected edit request on 2 March 2014

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[1] 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?

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

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 ?