Talk:Pi

Tau needs attention

Editors (both from [1], meat puppets?) appear to be trying to recreate Tau_(2π) contrary to prior discussions. Can some others keep an eye? IRWolfie- (talk) 23:59, 11 March 2013 (UTC)

Don't look at me. I don't know anyone from Sweden. Why do you suspect they are "meat puppets", rather than just people interested in tau but not interested in following the rules? (Serious question, not rhetorical) --Joseph Lindenberg (talk) 00:29, 12 March 2013 (UTC)

Is there anything controversial about the following removed sentence? "Salman Khan, named in Time's 2012 annual list of the 100 most influential people in the world,[149] advocated the use of τ before π in one of his educational videos at Khan Academy.[150]" –St.nerol (talk) 01:47, 12 March 2013 (UTC)

It's implicitly making the argument that, because Khan was named by Time, his opinion is particularly noteworthy to the issue of τ. That is an example of what is sometimes called "synthesis" in the original research policy. In fact, it is not at all clear whether Khan's opinion about mathematics is important to the mathematical community. I am not sure that Khan Academy is particularly well regarded. — Carl (CBM · talk) 01:54, 12 March 2013 (UTC)

Might do better describing his importance in math education. A VERY LARGE number of people do learn math from Salman Khan, so while the "mathematical community" may look down their nose at his math expertise, he's an undeniably important figure in math education. By the way, where you wrote "τ before π", I think you meant "τ instead of π". --Joseph Lindenberg (talk) 02:03, 12 March 2013 (UTC)

It's not clear whether Khan has credibility in the mathematics education community, e.g. http://chronicle.com/blognetwork/castingoutnines/2013/02/05/khan-academy-redux/ as a starting point into the discussion. I would wager there has been much more discussion of Khan Academy in the mathematics education community than in the mathematics research community. — Carl (CBM · talk) 02:15, 12 March 2013 (UTC)

Just because he has critics in the math education community doesn't mean that the community in general sees him in a negative light. That's true with any expert community. --Joseph Lindenberg (talk) 02:27, 12 March 2013 (UTC)

In any case, the point about the sentence is that it is making two separate arguments: (1) that the Time mention indicates Khan's opinion about τ is valuable and (2) Khan has expressed support for &tau. Point (1) is far from clear to me - why would inclusion on Time's list indicate any particular expertise about τ? Moreover, even if it did, why would Khan's opinion be more valuable than the actual mathematicians whom we already know have written things supporting τ? Khan seems like a particularly odd choice for an example of someone who speaks for the consensus of the mathematics or mathematics education communities, given that he is not really part of either of those communities. — Carl (CBM · talk) 02:34, 12 March 2013 (UTC)

Who said we could only quote people who speak for the consensus of an entire expert community? Salman Khan's opinion matters in math education. He's head of a very large (in terms of numbers of students) educational organization. So much so that I don't think you need to explain at length who he is. "Salman Khan, founder and CEO of the online learning resource Khan Academy, advocated the use of...". Everyone knows Khan Academy. Wikilink Salman Khan (educator) and Khan Academy for people who don't. --Joseph Lindenberg (talk) 02:54, 12 March 2013 (UTC)

"Salman Khan's opinion matters in math education." - that is exactly the claim I am disputing. The sentence in question tries to argue that his opinion matters because the Time list mentions him. But, much as is the case with τ, it is too soon to see what influence Khan will have on mathematics education, and there is no reason apart from faith to think that τ will become widely accepted or that Khan will have a lasting influence. — Carl (CBM · talk) 03:06, 12 March 2013 (UTC)

Yeah, I agree citing Time isn't the way to go. But just because a man hasn't completely transformed how everyone learns math in this country doesn't mean we can't quote him in the article. The stats in the Khan Academy article make clear just how big they are, and Salman Khan steers (and built) that ship. Just by virtue of what he chooses to do at Khan Academy alone, his opinion matters in math education. After saying all this though, if you and St.nerol decided that mentioning Stephen Abbott's endorsement would be more agreeable to everyone, that's fine too. I'm going to bed. --Joseph Lindenberg (talk) 03:37, 12 March 2013 (UTC)

The problem is that adding any more material on tau - regardless of how outstanding the source is - would violate the WP UNDUE policy, because it would give readers the impression that tau is more important that it is. Tau already has about 1% of the pi article (just a rough guess) ... yet in the math literature, tau has about 0.00001% as much weight as pi. Increasing the text in the article above 1% would give readers the erroneous impression. Any more details about tau can go into an article dedicated to tau, not here. --Noleander (talk) 03:48, 12 March 2013 (UTC)

That's why a separate article for tau would in doubt be appropriate. Personally I would support such an article alone to get rid of the neverending and somewhat naueating discussions here. Tau has cenrtainly seen enough media attention to warrant its own article, even if it just seen as popular science/cultural phenomenon.--Kmhkmh (talk) 17:42, 20 March 2013 (UTC)

The solution to the "nauseating discussions" is to create a separate "arguments" page, as at 0.999.... Actually, the media attention has died down since the initial sensationalist burst two years ago. Wikitalkpage verbiage is not a valid reason for creating a page. Tkuvho (talk) 17:46, 20 March 2013 (UTC)

I think you misread my (sarcastic) comment somewhat. Avoiding nauseating discussion is of course no proper reason to create articles and I have no objections against the arguments page. I do believe however tau is as (pop or internet) phenomenon well known enough to have its own article, which as consequence then also solves the problem of edits here (on the article) and the WP:UNDUE issue (within the the article). Meaning a more detailed description of tau is certainly inappropriate (undue) within the pi article, but obviously not when having an article on its own.--Kmhkmh (talk) 12:16, 22 March 2013 (UTC)

When I started editing Wikipedia I was taught that sentences should not just state stuff, but exemplify why it is relevant. It seems to me that was what the deleted sentence tried to do. Does naming a notable proponent gives tau undue wheight? Well, then that'd be because the rest of the article is too short. With your reasoning we should also go straight ahead and e.g. remove the three sections about creationism from the article of evolution. –St.nerol (talk) 11:04, 12 March 2013 (UTC)

The problems with the sentence are (1) it is not clear how "strongly" he is a proponent; all I see is that he made a video about τ. Has he done a lecture tour on it? Has he written a textbook that uses it? The sentence mentions his name but there is no way, at the moment, to tell exactly what his contribution is. (2) If the goal was simply to mention that Khan supports τ (whatever that means, cf. 1), then there is no need to mention the Time article. Really, the problem is that there is not enough reliably sourced material about τ which is what makes it tempting to look for anything at all related just to have something to say. But the solution to that is to wait until there are enough good sources before trying to write much. — Carl (CBM · talk) 11:51, 12 March 2013 (UTC)

It appears that Salman Khan (educator) has his own page (if this is the same person as discussed above). If so, providing the link to his page is sufficient. Any additional adjectives should be removed as WP:PEACOCK terms. Tkuvho (talk) 15:01, 12 March 2013 (UTC)

WP:PEACOCK says that one shouldn't use terms like legendary, great, etc; but just describe the facts. The non-peacock example given is: "Dylan was included in Time's 100: The Most Important People of the Century, where he was called "master poet..." –St.nerol (talk) 19:14, 12 March 2013 (UTC)

John Machin inaccurate

The John Machin method is inaccurate past the 16th digit. See WolframAlpha. --72.219.142.167 (talk) 20:29, 6 April 2013 (UTC)

• That is showing the limits of wolframalpha, not John Machin's formula. Try it on something else, say Pari/GP, which can handle multiprecision values. John W. Nicholson (talk) 01:51, 7 April 2013 (UTC)

The fallacy of Point, Line and the Death of Pi

Please review WP:NOTFORUM as articles talk pages are not a place to discuss new ideas that are not based on reliable sources. Johnuniq (talk) 07:02, 12 April 2013 (UTC)
The following discussion has been closed. Please do not modify it.
1. Any point in 2-dimension or 3-dimension is not a point, unless below described exceptions Consider the points below: .... Which of the above is a point – fourth dot or fifth dot (so small, that it can not be seen with the naked eye)? If we enlarge the fourth point and the fifth point with a lens or a microscope, we will see it as big as probably the first dot, if not bigger. Thus, the fourth and fifth points are spheres (or something else) and they are not points. However small and accurately we describe the position of the point, it will still have a left, right, above and below to it, besides the sides / diagonals. The position of a point can be defined only if the coordinates are in multiples of 1 or other exceptions below. Also, it will not be possible to represent the point diagrammatically, even if all its coordinates are in multiples of 1. If we put a point in that coordinate, then, some part of the point will be above the coordinate, some part below and so on. Even here, it is only a hypothetical point and any attempted representation of the point will only be an approximation, with the spreading across of the minute point (when enlarged through a lens, as described above). Exclusions: The fact of the matter is that there is no point in 2-D or 3-D, excluding certain exceptions. Let us take 2-D for starters. If we have coordinates of (1, 2), then 1 and 2 being whole numbers, this will exactly represent a point in 2-D with respect to origin i.e. (0,0). A point with the coordinates in 2-D of (3.23, 4.69) cannot be a point. This is because, 0.23 lies between 0 and 1 or between 0.22 and 0.24. What it means is that if it is not in multiples of 1 or an equally divided proportion of 1 and its multiples, then it cannot be a point. If we take 1m as the length of a line, then the line can be divided into exactly equal and measurable parts only by 2, 5 and multiples and powers and other combination of products and powers of these two numbers; of parts. This is so, because 1 cannot be divided into exactly 3 equal parts; nor 6; nor 7; nor 9. But, it can be divided into 2, 4, 5, 8 equal parts. It can also be divided into 1000 equal parts or 25 equal parts. This is so because; the division of 1 by the other numbers does not have a finite number of decimal places. So, how much ever precision we go to, we can never represent any point accurately, with the other decimal representations. So, (1, 1.1) can be represented for a point and similarly, (1, 1.25) can also be represented. But not (1, 1.35). 2. Any line is not a line; except the hypothetical line measuring in length as above Consider below lines (assume of varying widths): ________ ________ ________ ________ Similar to a point, a line, too, cannot be represented as a line. For, which of the above 4 lines is a line and which are combination of multiple parallel lines? Same as above, if we expand the third and fourth (so small, that it is not visible to the naked eye) lines under a microscope, we will see it as big, if not bigger that the first line. Obviously, the first one is not a line and similarly, other 3 are also not lines. Any straight line drawn is as good as a rectangular thin rod (or something else), as we will have points on the line, which will be like other geometrical objects like sphere, etc. So, a straight line is only a hypothetical line, joining two points that can be defined as above. In reality, it would not exist. When it comes to the length of a line, again, it has to be as described in the previous point (point no. 1). Otherwise, it will have a range of length. Let us see how? If we have a length of a line of 1 m, then it is exactly measurable. However, if we have the length of a line which is not in multiples of 1 or multiples of parts of 1 divisible by any combination product / power of 2 and 5; then, it is never a line. In those cases (e.g. 2.53 m), the line is not a line, it is a function of numbers, whose size falls between 2.5 m and 2.625 m (which are multiples of 1 + numeric multiples of equally divisible parts of 1 i.e. divisible by 4 and multiples of 8 and hence exactly measurable). Thus, any line is hypothetical, like points. And any two points in space (even if defined as per point no.1) will never be able to form a line, unless the length of the line joining the two points (shortest distance between the two points) is as described in this section. And, if they don’t follow this principle, then the distance between the two points can never be measured accurately. 3. A circle can have diameters only as defined above in point no.2 Any line (even if hypothetical) will have a measurable and constant length, only if the previously stated conditions hold for the length of the line. Thus, this holds for even the diameter of a circle. Thus, any diameter other than of length as described in point no. 2 is neither measurable, nor constant. And, if the diameter is neither constant nor measurable, then, it cannot form a perfect circle. Thus, you can have a diameter of 1 m or 1.5 m; but not a diameter of 1.59 m. Or maybe, you can also have a diameter of 1.59 (= 1 + ½ +1/25 + 1/20); which the mathematicians should ascertain. In this case, by rotating the diametrical line by 360 degrees, we will get a circle – or we thought so! Let see more surprise below. 4. The circumference of a circle can never be determined Assume that the diameter of a circle is 1 m. Then the circumference of the circle = π x d = π. The circumference of a circle is nothing but a straight line of same length as the circumference, turned into a circle. Thus, the length of the line representing the circumference is π, in this case. However, π is not a number that can be represented in any of the manner mentioned in the previous point nos. 2 and 3. That is, it is not a finite number, which can measure a line accurately and precisely. It is represented by an infinite series. So, definitely, it cannot be a measurable and constant length, as should define a line or the length of the circumference of this circle. Thus, if we were to split the circle at any point and then stretch the two ends to form a line, then, if the length of this line is π or any multiples thereof, then it is definitely not going to be measurable or constant or finite. Anything finite (circumference of a circle) cannot be represented by and infinite number / series. Although π is termed to be a constant; since it does not follow the above rules, it is not a measurable constant for a line; and, hence for the circumference. Thus, there are two options: a. Either π x d is not the circumference of a circle or b. The circumference of a circle can never be determined accurately, despite an accurate and measurable diameter. And a circle can be formed only by a measurable diameter, as described above. E.g. 1/3 meters can never be the diameter of a circle, as it is not finite. Likewise, 1/6 or 1/7 or 1/9 meters also cannot be the diameter of a circle, as the resulting fractional number is not finite and the length of the line is not an exact equal divisor of 1. In case (a), mathematicians have to determine the new circumference of a circle, if it is exactly measurable from point to point. In case (b), what it means is that the so calculated circumference of the circle is either less or more than the point to same point distance traversed through the circumference of the circle. What this means is that, a circle as defined generally as traversing from one point to the same point around a 360 degree arc, around a center, with the same diameter, is never possible in reality to draw. Thus, we always draw somewhat lesser or somewhat more of a circle. In other words, a circle can only be defined as an infinite loop, with no beginning or no end, with every point in the circle being exactly the same distance from a central point. Of course, the distance of each point from the center should follow the above description of a proper line (point nos. 2 and 3). Conclusion: It is thus, for the mathematicians to define the exact laws and review formulaes again. For, this article can sound the death knell for the most vouched for and most wowed constant π! I am sure the above theories will apply to all geometrical figures, their lengths, their circumferences, their areas, their volumes and so on. --Annienaras (talk) 14:48, 11 April 2013 (UTC) No. You are wrong. You're taking elements like construction errors and line thickness, and pretending they're part of the geometry. They aren't; they're just noise. Points have a good, clear definition as 0-dimensional entities in n-dimensional space, and circles, spheres, etc, are similarly clearly defined. Also, some of your diagrams are missing. AlexTiefling (talk) 14:53, 11 April 2013 (UTC) I don't think it's even wrong -- just incoherent crank nonsense, of a fairly usual type. Can't contributions like this simply be deleted? Imaginatorium (talk) 19:34, 11 April 2013 (UTC) We need a Talk:Pi/Arguments page (similar to Talk:0.999.../Arguments) where opinions and discussions about π should go. They don't belong here in the Talk page, since this is reserved for discussions about improving the article, and not about π itself. — Loadmaster (talk) 02:16, 12 April 2013 (UTC) Just hat it and the replies instead: it takes up no more space, should not distract other editors (except the few that check the contents) and is easily found by the original poster if they want to revisit the discussion (if it's moved they may think we delete such comments). If we get more maybe add an edit note with suggestions.--JohnBlackburnewordsdeeds 03:12, 12 April 2013 (UTC) Why PI x D cannot represent the circumference of a circle? Gentlemen, I accept your comments; however, please look at the below logic, which explains my rationale better: When the circumference of a circle is straightened (by stretching the two ends), it becomes a line or vice-versa. Length of a line has to be always finite. You cannot have an infinite representation as length of a line e.g. 1 1/3 metres. 1/3 is not an exactly and equally divisible part of 1. It is 0.3333333....... So, we can have length of a line as only say 1.33, which can be represented as 1+1/4+1/25+1/25. Thus, a line of 1 meter can be divided into exact equal parts of 2, 4, 5, 8, 10 and so on. Any infinite decimal cannot represent exactly a line of finite length. It will only be an approximation; it can never be exact. Such lines are just hypothetical; in reality they are undefinable / non-existing. Anything that has a finite length (circumference of a circle) cannot have an infinite measurement of the same. Thus, for a diameter of 1, circumference = Pi = 3.14159.... If we approximate to 3.14, then it is less than the exact circumference. If we approximate to 3.1416, it is more than the exact circumference. For diameter = 1, circumference = Pi. Pi is not an exact finite number. We cannot have lengths in fractions, of a line, which are not finite. So, if Pi x D is the circumference of a circle; then it is always indeterminate, exactly. So, we can never determine the circumference of a circle exactly; which means that a circle can never be drawn as starting at one point and ending at same point, with all points equi-distant from the center. What it also means is that, the current formula of determining the circumference of a circle is not appropriate. If at all it is possible to determine the circumference of a circle exactly, then a new formula needs to be devised and it should have a finite result (in terms of number of decimal places). Otherwise, you cannot define a circumference of a circle exactly. You will be something more or something less than the exact circumference, always. What we draw is just a continuous loop. So, a circle has no beginning or end. It is just an infinite loop. Annienaras (talk) 04:22, 12 April 2013 (UTC)

Why does Π redirect here?

I don't think I've ever seen Π used for the circle constant, ever. It's production, just about always, isn't it? Twin Bird (talk) 18:16, 24 April 2013 (UTC)

(Aside...) I think you mean "product" for Π. I do not think "production" means "multiplication"! Imaginatorium (talk) 17:13, 25 April 2013 (UTC)

Mediawiki does not distinguish between having the first letter of an article capitalized or uncapitalized. So Π and π are the same article, which is a redirect to this page. — Carl (CBM · talk) 18:32, 24 April 2013 (UTC)

I've long felt that the first-letter-case-insensitivity should apply only to letters from the Latin alphabet (with or without diacritics). But Brion is exquisitely uninterested in making such a change. --Trovatore (talk) 20:11, 24 April 2013 (UTC)

Physics/engineering

I think Simple Harmonic Motion rates a mention. Pi crops up whenever we are discussing things that oscillate or wobble. — Preceding unsigned comment added by Paul Murray (talk • contribs) 05:14, 1 May 2013 (UTC)

Pi#Physics isn't good enough for you? --Izno (talk) 12:38, 1 May 2013 (UTC)

Closed RFC on Tau (2pi)

See User talk:Tazerdadog/Tau (Proposed mathematical constant) at the bottom. Chutznik (talk) 19:26, 6 May 2013 (UTC)