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Pi Day Is Coming — But Tau Day Is Better

Soulskill posted more than 2 years ago | from the circular-logic dept.

Math 241

PerlJedi writes "A few months ago, a Tweet from Randal Schwartz pointed me to a YouTube video about 'Triangle Parties' made by Vi Hart. My nerdiness and my love of math made it my new favorite thing on YouTube. Now, with Pi Day coming up later this week, I thought it would be an appropriate time to point people to another of her YouTube videos: Pi is Wrong. The website she mentions at the end, Tauday, has a full explanation of the benefits of using Tau rather than Pi. Quoting: 'The Tau Manifesto is dedicated to one of the most important numbers in mathematics, perhaps the most important: the circle constant relating the circumference of a circle to its linear dimension. For millennia, the circle has been considered the most perfect of shapes, and the circle constant captures the geometry of the circle in a single number. Of course, the traditional choice for the circle constant is pi — but, as mathematician Bob Palais notes in his delightful article "Pi Is Wrong!", pi is wrong. It's time to set things right.'"

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Agreed (5, Funny)

Ardeaem (625311) | more than 2 years ago | (#39329039)

What, pi is 14.3? When did that happen?

Re:Agreed (4, Funny)

Harold Halloway (1047486) | more than 2 years ago | (#39329169)

Being English, old-fashioned and inaccurate, I prefer to celebrate Pi Day on July 22nd.

Re:Agreed (5, Interesting)

wjh31 (1372867) | more than 2 years ago | (#39329245)

22/7 is actually more accurate than 3.14 (0.05% vs 0.04%)

Re:Agreed (1)

Hatta (162192) | more than 2 years ago | (#39329773)

22/7 is misleading, in that people often think it's an exact value. I actually had math teachers in middle school who claimed as much, and refused to understand the term "transcendental number".

Re:Agreed (1)

DMiax (915735) | more than 2 years ago | (#39329835)

nevermind trascendental, did he ever hear about irrational?

Re:Agreed (2)

Hentes (2461350) | more than 2 years ago | (#39329173)

Because that's not the standard [wikipedia.org] .

Re:Agreed (2)

uigrad_2000 (398500) | more than 2 years ago | (#39329183)

Dude, you put the more significant digits first.

Pi is now 201203.14 (201.203,14 with European punctuation).

Re:Agreed (1)

Carewolf (581105) | more than 2 years ago | (#39329581)

Actually with European punctuation it is 14/3 - 2012 which is around 2008BC or something

Re:Agreed (0)

Anonymous Coward | more than 2 years ago | (#39329405)

Columbus.

Re:Agreed (1)

Oswald McWeany (2428506) | more than 2 years ago | (#39329669)

What, pi is 14.3? When did that happen?

It is a consequence of neutrinos going faster than light- all the laws of the universe are now backwards. And yes, Pie is now 14.3... or as an estimation 7 divided by 22.

Re:Agreed (2)

Oswald McWeany (2428506) | more than 2 years ago | (#39329761)

[whistling to self] hope no-one notices how I spelt pie... [/whistling to self]

Cant eat a slice of Tau to celebrate. (5, Insightful)

Kenja (541830) | more than 2 years ago | (#39329047)

Thing is, we like pie. Being able to eat a Pi sized slice of Pi at 1:59 on 3.14 is a geeky excuse to consume treats.

Re:Cant eat a slice of Tau to celebrate. (1)

Kozar_The_Malignant (738483) | more than 2 years ago | (#39329349)

You beat me to it. I'm the chief promoter of Pi Day at my workplace, and it's mostly almost all about the pie. One of the secretaries likes to sing Pi Carols, but it's pretty much about the pie eating.

Re:Cant eat a slice of Tau to celebrate. (1)

Oswald McWeany (2428506) | more than 2 years ago | (#39329741)

I'm trying to imagine Pi Carols...

Oh Pie Tree, Oh Pie Tree,
How lovely is your crust baked...

Rudolf the red cherry piedeer

We three fillings, of orient are,
figs, plums, kiwis stored in a jar

Timer Bells, Timer Bells
Time to open the oven

Re:Cant eat a slice of Tau to celebrate. (2)

gstoddart (321705) | more than 2 years ago | (#39329819)

One of the secretaries likes to sing Pi Carols

Wow, is your secretary some kind of frustrated geek or something?

I didn't even know there were Pi carols.

Re:Cant eat a slice of Tau to celebrate. (2)

sideslash (1865434) | more than 2 years ago | (#39329549)

If you want to observe the festivities with a more phonetically accurate English language reinterpretation of the ancient Greek letter name "Pi", you should go to the restroom and urinate. That can be a very satisfying feeling as well.

Re:Cant eat a slice of Tau to celebrate. (4, Insightful)

buchner.johannes (1139593) | more than 2 years ago | (#39329667)

With Tau, you can have two pies.

Wait what? (2)

BenJury (977929) | more than 2 years ago | (#39329059)

There are 14 months in a year now?

Re:Wait what? (1)

CaptSlaq (1491233) | more than 2 years ago | (#39329135)

It's the year 3141?

Re:Wait what? (2)

ae1294 (1547521) | more than 2 years ago | (#39329317)

Well with everyone so interested in the Mayans with thought; Oh, the Mayan calendar is 13 months long. We're gonna make ours 1 better you see? 14 is 1 better than 13. Our new calendar goes to 14!

Re:Wait what? (0)

Anonymous Coward | more than 2 years ago | (#39329987)

Depends which calendar you use. There could be 19 months of 19 days in a year, with 4 (or 5 for leap year) Intercalary days to make up the number.
And that would mean we were in the 19th month (Loftiness)

Submitted by Hipster Cat? (0)

Anonymous Coward | more than 2 years ago | (#39329071)

Next year there will be a post along the lines of "I liked Tau day before it was cool."

Triangle Panties (1, Funny)

cpu6502 (1960974) | more than 2 years ago | (#39329081)

Darn.
  I read that wrong.

I say we stick with pi. It's too labor-intensive to rewrite all the textbooks to read "tau" instead of "2*pi" and reteach everyone the new formulas.

Re:Triangle Panties (1)

RandomChars (1455331) | more than 2 years ago | (#39329507)

nevermind the fact that tau is already the symbol for a bunch of other things. I think it would make more sense to redefine pi as whatever new constant you wanted, but then that would be about 60billion times more confusing.

Re:Triangle Panties (3, Insightful)

Grishnakh (216268) | more than 2 years ago | (#39329925)

It is? Like what? There's a lot of greek symbols that are used for different things, so you have to look at what domain you're in before you make any assumptions about their values. This also applies to latin symbols.

Quick: what is i? Well, that depends. If you're a mathematician, it's the square root of -1. However, if you're an electrical engineer, the answer is the AC current. In EE, j is the square root of -1. Omega, theta, tons of symbols like these are reused in different domains for different things.

Offhand, I don't remember tau being used for anything else in mathematics (specifically geometry), so it seems as good a symbol as any. According to Wikipedia, there's a handful of mathematical uses for tau already, but they seem pretty esoteric (or obsolete, in the case of the golden ratio, which more commonly uses phi). It is used for a bunch of things in physics and biology, but those are different domains, so that's pretty irrelevant. You don't use pi (the circle constant) much in biology either, I imagine.

However, there are some greek letters that are barely used, so maybe one of those would be better. Upsilon, for instance, only has one use listed in Wikipedia's list of greek letters used in math, science, and engineering, to represent an elementary particle. Only physicists would ever see that (I don't think I ever saw that in college, as I was a EE major), so maybe that'd be a better choice than tau.

Re:Triangle Panties (1)

newcastlejon (1483695) | more than 2 years ago | (#39330205)

Tau is used for both torque and shear stress (among others) in mechanical engineering. The former would cause quite a headache considering how often pi comes up in rotating systems.

Re:Triangle Panties (1)

rossdee (243626) | more than 2 years ago | (#39330023)

Yeah, sounds like a Tau of Babel to me

Re:Triangle Panties (4, Insightful)

Mr Z (6791) | more than 2 years ago | (#39329975)

And, I think it's perhaps a little wrongheaded anyway. The area of a circle is pi*r^2. That'd become tau*r^2/2... You took the 2 out of one place and put it in another. And it does nothing for spheres: Volume = (4*pi*r^3)/3 = (2*tau*r^3)/3; Surface area = (4*pi*r^2) = (2*tau*r^2).

And besides, tau's already claimed as the "time constant" variable, so n'yah!

Tau day is better (5, Funny)

Bob the Super Hamste (1152367) | more than 2 years ago | (#39329121)

Tau day is better because I have an excuse to get 2 pies instead of just one. I still celebrate pie day as well as groundhog day, mmmmm ground hog).

Re:Tau day is better (1)

Anonymous Coward | more than 2 years ago | (#39329421)

I think steak and blowjob day beats them both.

Re:Tau day is better (1)

Bob the Super Hamste (1152367) | more than 2 years ago | (#39329909)

Now if only I could convince my wife it actually existed.

Re:Tau day is better (1)

gstoddart (321705) | more than 2 years ago | (#39330249)

Now if only I could convince my wife it actually existed.

Surely she's capable of verifying that with a google search.

Convincing her it's anything other than a geek thing, well, that might be tougher. :-P

Re:Tau day is better (1)

BobNET (119675) | more than 2 years ago | (#39329947)

Tau day is better

But Einstein's birthday is best!

FUCK Tau day (1)

LanMan04 (790429) | more than 2 years ago | (#39330303)

I'll never support those filthy Xeno bastards.

Pi day will always remain the same for me (1)

ackthpt (218170) | more than 2 years ago | (#39329125)

It's the day we're all comfortable with Sin(), further we're so accomodating we'll embrace Cos().

Re:Pi day will always remain the same for me (1)

RyuuzakiTetsuya (195424) | more than 2 years ago | (#39329723)

tau day is better in this regard. It's easier to get a Tan() in June than march.

Did someone say Tau (0)

Moheeheeko (1682914) | more than 2 years ago | (#39329167)

I refuse to celebrate xenos and heretics! The Emperor wills it!

Breaking derivatives (0)

Anonymous Coward | more than 2 years ago | (#39329193)

Every Pi Day this tau crap comes around with the pseudomathematics community forgetting that using tau instead of pi in the way their way would change the lovely fact that d sin x/dx = cos x.

Re:Breaking derivatives (1, Insightful)

tigre (178245) | more than 2 years ago | (#39329287)

No, it doesn't. Just using a different scale (x = 2y).

Re:Breaking derivatives (1)

TarMil (1623915) | more than 2 years ago | (#39329477)

What the fail? Using tau wouldn't change anything to the properties of cos and sin.

cos x and sin x are defined as the abscissa and ordinate of the point on the unit circle associated with an arc of length x. How does the name of a constant change anything to this definition?

Considering the counterpoints (3, Interesting)

Anonymous Coward | more than 2 years ago | (#39329203)

I do think tau is the 'better' constant, and both exploring the possibilities of what tau can do, and just 'playing around' with the math involved, has been enjoyable. However, to evaluate it properly and determine just how strong it is, a strong counterpoint is needed - and it is supplied in The Pi Manifesto [thepimanifesto.com] .

Both its author and I recommend reading The Tau Manifesto (and Bob Palais's original work; both are linked in the article above) before reading The Pi Manifesto, to make proper sense of it.

In the end, I think tau is a much stronger choice than pi for some aspects of math; others, deserve further investigation. It may all be academic discussion, given how firmly pi is entrenched in our mathematics, but perhaps there's a solid place for both - with pi reserved for certain advanced concepts, and tau used through introductory geometry, trig and calculus.

Re:Considering the counterpoints (0)

thomasw_lrd (1203850) | more than 2 years ago | (#39329695)

Dammit I'm American, and I refuse to learn new math just because it makes more sense. I will continue to to try and memorize that there are 12 inches in a foot, 3 feet in a yard, and dammit, I forgot how many feet in a mile. To hell with the metric system.

Re:Considering the counterpoints (3, Interesting)

Grishnakh (216268) | more than 2 years ago | (#39330061)

The imperial system actually makes more sense for some things, depending on which measure you're talking about and what you're using it for. The whole 12 inches/foot thing can be easier to work with when you have to divide things evenly in quarters and thirds; by having something divisible by 12 instead of 10, you can easily divide by 3 or 4 without the math becoming complex. That's the whole reason 12 was the base for these units; back in medieval times, when they didn't have calculators and measurements were crude, it was easy to work with. Even now, woodworkers generally prefer English units for this reason.

Miles, however, don't make so much sense since they in fact are equal to 5280 feet. The big problem with conversion however, at least here in America, is that many things are based on miles. For instance, here in Phoenix, all the main streets are laid out along a 1-mile grid system. It's stupidly easy to see how far you'll travel from one point to another (using Manhattan lengths; except for Grand Ave, all the roads are N-S or E-W) just by looking at a map and counting the number of main roads in each direction. If we tried to convert to km, it'd be a mess. If I ask "How far is it from Baseline to Ray?" the answer is a simple "5 miles", just by counting the roads in between (Guadalupe, Elliot, Warner, Ray). In km, I'd count the roads and then multiply by 1.6, getting 6.4km, not exactly a convenient measure.

Four thirds pi! (5, Interesting)

Geoffrey.landis (926948) | more than 2 years ago | (#39329209)

Wait, what about four-thirds pi, the constant that relates the volume of a sphere to the radius???

Using 2pi as the so-called "constant" is two-dimensional chauvinism!

Re:Four thirds pi! (1)

Carewolf (581105) | more than 2 years ago | (#39329727)

4/3 pi r^3 is actually 2/3 or of a circumscribed cylinder or 2/3 tau r^3..

This tau thing kind of makes sense, though I tend to call it 2 pi.. If pie is good, two pi is twice as good.

Re:Four thirds pi! (1)

lzygenius (825602) | more than 2 years ago | (#39330035)

Using tau you can use two-thirds tau to relate the volume of a sphere to the radius.

Re:Four thirds pi! (1)

DMUTPeregrine (612791) | more than 2 years ago | (#39330059)

Bah, use (pi^(n/2)*r^n)/gamma(n/2+1), the volume of an n-dimensional ball related to its radius and the number of dimensions!

Re:Four thirds pi! (0)

Anonymous Coward | more than 2 years ago | (#39330097)

Add to that the fact that for every 4/3 of pi you only get back 2/3 of tau! Fiscally irresponsible, I say.

Seems pretty unimportant (1)

Anonymous Coward | more than 2 years ago | (#39329221)

So Tau is C/r, Pi is C/d. Who cares? One is twice the other.

That reads to me like "4 is wrong! Use 2, and square it!"

I don't see how one is "right" and one is "wrong". If it significantly makes a particular equation or formula easier to read, go ahead and make the first line of your proof be "Let tau = 2*Pi" and get over yourself.

Re:Seems pretty unimportant (1)

Grishnakh (216268) | more than 2 years ago | (#39330173)

It's not that one is right or wrong, it's that one is easier than the other, and simplicity and elegance are always preferable to needless complexity.

For an extreme example, let's say that for some reason, people teaching math classes all suddenly decided to replace pi with a new constant, called Q, which is equal to pi * 13/59. Why? Just to make life difficult for everyone. So now, you're trying to teach little kids about simple geometry, and telling them that the circumference of a circle is 118/13 * Q * r, or 59/13 * Q * D. And they'll need to do all the math involving circles and arcs with these extra factors of 59 and 13. It should be pretty obvious that this will be a giant PITA. The authors of the proposal make a very good case that pi really doesn't make much sense, because you constantly wind up with extra factors of 2 everywhere in your equations, for no good reason, and by using tau (2 * pi), all the equations are suddenly much simpler. Obviously, the difference isn't as great as with my crappy "Q" constant, but it's still there.

pi is silly (1)

Anonymous Coward | more than 2 years ago | (#39329327)

Why are we still using pi? I mean, if pi = 3, then why don't we just use the number 3 and get rid of pi? It's useless.

Re:pi is silly (1)

Canazza (1428553) | more than 2 years ago | (#39329465)

Because Pi is closer to 4 than it is to 3. If you're playing the Price is Right it is anyway.

Re:pi is silly (1)

Anonymous Coward | more than 2 years ago | (#39330251)

Or just stop using damn circles. Everyone knows that nature is all about straight lines and linear vectors, these man-made curved abstractions are only confusing an already-difficult subject. I mean, really, how the hell does Pi apply to a balance sheet? Stop the insanity!

Bah. e is better than them all (2, Interesting)

Matt_Bennett (79107) | more than 2 years ago | (#39329341)

Who cares about pi or tau? e shows a much more in depth understanding of mathematics.

Re:Bah. e is better than them all (5, Funny)

Bob Hearn (61879) | more than 2 years ago | (#39329413)

Then, when somebody wants to argue that twice e is actually a better constant, we can say "2e or not 2e, that is the question."

Re:Bah. e is better than them all (1)

arth1 (260657) | more than 2 years ago | (#39330053)

we can say "2e or not 2e, that is the question."

Unless you use the Amerenglish pronunciation[*], you can say:
"2 pi or not 2 pi, that's the tau question".

[*]: At least they're mostly consistent, making "pi" rhyme with "bi-" and "Semper Fi". But not with "quay".

Re:Bah. e is better than them all (0)

Anonymous Coward | more than 2 years ago | (#39329485)

I say we put the tau folks in charge of updating all the world's software then. Well? I'm waiting...

Re:Bah. e is better than them all (1)

effigiate (1057610) | more than 2 years ago | (#39329625)

I also came here to suggest an "e" day. I know that I use e much more frequently than pi.

Re:Bah. e is better than them all (0)

Anonymous Coward | more than 2 years ago | (#39329751)

When you start doing real work, the constant factors all get tossed away and then put back in at the end. Take special relativity -- you pick your units h-bar=c=1 and then express mass in energy units etc. It gets a little weird when you start working out units of magnetic fields but for a lot of common calculations it's helpful. If you need to weasel your results around to get a measurable quantity then you figure out what constants to put back in as a unit conversion.

"American PI Day" (0)

Anonymous Coward | more than 2 years ago | (#39329365)

It's not PI, but 14.03 for majority of the world.

Re:"American PI Day" (1)

Stickybombs (1805046) | more than 2 years ago | (#39329493)

That's fine, you guys can celebrate and eat your pie on the 3rd of.....whatever month comes 2 after December. We prefer ours now! Have to keep up the stereotype of the fat Americans :)

Re:"American PI Day" (1)

king neckbeard (1801738) | more than 2 years ago | (#39329725)

The ISO standard is YYYY/MM/DD, and that is used by China, Japan, and anybody who likes files and folders to be properly organized. The US system fucked up on the placement of the year, but is the same when the year is left out.

Re:"American PI Day" (1)

Grishnakh (216268) | more than 2 years ago | (#39330241)

The system I normally use is DDmmmYYYY, where mmm is a three-digit abbreviation of the month. I believe it's the standard for the US military. So today, for instance, is 12MAR2012. This system works well since there's no confusion about its meaning; since the middle three letters are obviously the month, and the last 4 obviously the year, the first two are obviously the day. Anyone in any country (at least who knows the English names of months, or can understand them well enough (most European languages have the same first 3 letters, or are very close)) should be able to read it and figure out what it means quickly instead of trying to think "was the person writing this date an American, and likely using MMDDYYYY? Or maybe they were an American, but they were writing for an international audience and thus using DDMMYYYY; how do I tell?"

Tau for the win (3, Funny)

mjrauhal (144713) | more than 2 years ago | (#39329373)

Tau is twice the constant Pi ever was!

Pie are not squared! (1, Funny)

jd2112 (1535857) | more than 2 years ago | (#39329407)

I remember arguing with my geometery teacher years ago, she kept saying pie are squared. I can't recall ever seeing a square pie. (Cobbler perhaps but never a square pie.)

tau is wrong (1, Insightful)

w_dragon (1802458) | more than 2 years ago | (#39329423)

Division is harder than multiplication. Given the choice between sometimes multiplying by 2, and sometimes dividing by two, we should pick the constant that forces the multiplication. Also, e^(pi * i) is nicer than e^((tau / 2) * i).

Re:tau is wrong (1)

Anonymous Coward | more than 2 years ago | (#39329769)

The really beautiful identity is e^(i \tau) = 1.

Re:tau is wrong (1)

Ironix (165274) | more than 2 years ago | (#39329845)

e^(pi*i) = -1 vs. e^(tau*i) = 1

Re:tau is wrong (1)

DMUTPeregrine (612791) | more than 2 years ago | (#39330139)

e^(i*theta)=cos(theta)+i*sin(theta)

Re:tau is wrong (0)

Anonymous Coward | more than 2 years ago | (#39330231)

I think that e^(tau*i) = 1 is inferior because it only uses 4 of the 5 fundamental numbers of pure mathematics (as zero is not used) and only 2 of the 3 elementary operations (as addition is not used).

In fairness e^(pi*i)=-1 misses the point as well, but e^(pi*i)+1=0 cannot be improved upon as each fundamental number and each elementary operation is used exactly once.

Re:tau is wrong (1)

Anonymous Coward | more than 2 years ago | (#39330129)

You didn't watch the video, as she specifically goes out of her way to note and address Euler's formula, which you failed to even type in full.

e^(pi*i) = -1

Corresponds to

e^(tau*i) = 1

So it's actually cleaner and "nicer" than the pi equivalent, having one less mathematical symbol (the negation of the one). You would have realized this if you had watched the video or actually done the math.

Maybe you should have tried being informed BEFORE posting?

Re:tau is wrong (2, Informative)

artor3 (1344997) | more than 2 years ago | (#39330199)

I know that some people will point out that e^(tau * i) = 1, which they'll claim is nicer than e^(pi * i) = -1

But the most beautiful equation in mathematics is e ^ (pi * i) + 1 = 0. The five most fundamental constants, being combined with the three most fundamental operators (addition, multiplication, exponentiation -- sorry, tetration), all equaling out, with absolutely nothing extra. There's no way to make it work as elegantly with tau.

It's not Pi day (0)

Anonymous Coward | more than 2 years ago | (#39329463)

The last Pi day was in 1592. The next will be in 15926.

What I'm trying to say here, is fuck off you pretentious wankers!

"wrong" is a sensationalist word. (2)

deego (587575) | more than 2 years ago | (#39329573)

Seriously? People devote all this energy to replace a centuries-old constant by twice its value?

Isn't "wrong" a sensationalist word to use?

This is like many other things that are "wrong" - in the sense that there are technically better conventions to use, but the weight of history and inertia often keeps us from switching. Examples:

- Km vs. Mile. (SI units vs. Imperial..)
- Why are there 60 minutes per hour? Wouldn't it be better to have 100?
- Why do we use base 10 to express numbers? We should rather use base 8.
- Why 360 degrees? Why not 100 or 1000 (which is using base 8, of course, as mentioned above) instead.

Re:"wrong" is a sensationalist word. (1)

Oswald McWeany (2428506) | more than 2 years ago | (#39329855)

I'm in the minority I know- but I would be in favour of switching to a metric clock. Sure it would cause confusion at first. I'd be in favour of measuring degrees in fractions of 100 or 1000.

There again- I'm always in favour of confusion. It's always more fun than the status quo.

Re:"wrong" is a sensationalist word. (1)

deego (587575) | more than 2 years ago | (#39330081)

haha, same here - actually in favor of switching for that case. That one was a bad example, then, I guess.

Re:"wrong" is a sensationalist word. (0)

Anonymous Coward | more than 2 years ago | (#39330237)

Examples addressed:

- Metric vs. Imperial: This is a travesty that should be remedied as quickly as possible.

- 60 minutes and 360 degrees are both addressable by their qualities of ease of division. Since they are multiples of 12, they are divisible by more items, This makes navigational math easier, and taking fractions of hours easier as well.

- Base 8 is hard to conceptually teach to children as most of them don't have any natural multiples of 8 on which to learn to count that they carry with them. Part of the reason the old cultures used 60 and 360 was that they counted in duodecimal (base 12) systems. Likely developed because you can count to 12 on the back of your hand, as four fingers with three joints each gives you a nice grid of 12 items on which you can count.

Re:"wrong" is a sensationalist word. (1, Interesting)

Grishnakh (216268) | more than 2 years ago | (#39330299)

You complain about miles instead of km, but then you complain about using base 10? You're not even being consistent; if you favor base 8, then you should be against switching to kilometers or any SI unit for that matter, as their entire existence is based on the supposed superiority of base 10.

And why base 8? Why not base 12? 12 is evenly divisible by both 3 and 4, which is very useful in many real-world situations. 10 is only divisible by 2 and 5. 8 is only divisible by 2, so it really sucks to be honest. 8 (or 16) is good when working with computers since it's easier than binary, but that's about it.

It's 360 degrees for the same reason there's 60 minutes in an hour. Base 12. Remember, degrees have smaller units: minutes and seconds.

Tau (2, Interesting)

brianerst (549609) | more than 2 years ago | (#39329615)

I'm not a mathematician, but that Tau "article" seems to steal a few bases.

It whines about A=(pi)r2 while C=(pi)D and how that shows that diameter is fundamental. But that's not the way I learned it anyway - the formula was always C=2(pi)r. Radius was fundamental, not diameter.

Which is even more obvious when you go into spheres, where everything is based off radius (A=4(pi)r2, V=4/3(pi)r3).

If we use diameter, you have to remember additional divisors (4 for the areas, 8 for the volumes). I can't speak on whether the whole "one turn" argument would help understanding other concepts, but aside from people who are working to become mathematicians, I suspect that the fact that the radius-based "magic formulas" are simpler will keep them around...

p.s. What magic brew do you have to use to get Slashdot to accept HTML codes like pi? Or Unicode? Every attempt ended up getting stripped, so I went with (pi).

Re:Tau (0)

Anonymous Coward | more than 2 years ago | (#39329951)

The Tau article also recommend substituting diameter divided by 2 (D / 2) for radius (r). So instead of V = 4/3 * pi * r^3 , V = tau * D^3 / 12 , which is even easier to remember IMHO. A = tau * D^2 / 2 seems like a wash.

Slashcode strips Unicode and a lot of HTML entities.

Re:Tau (2)

DMUTPeregrine (612791) | more than 2 years ago | (#39330209)

A circle in n dimensions is defined as the set of all points at a given distance from a fixed point, the center. Circles are defined by the radius, not the diameter. The "standard" equation for a circle is x^2+y^2=r^2. Etc, etc. The diameter is not more fundamental.

It was something I always wondered... (0)

Anonymous Coward | more than 2 years ago | (#39329623)

... even during back in school, when I learned more equations with that thing in it, IT WAS ALWAYS 2PI! (well, few obvious ones weren't 2pi, such as spherical stuff)
It was maddening that the value they were using was "incorrect".

A few changes could be done to equations for those rare occasions where 2pi isn't used, which would kill 2 birds with one stone since you get rid of so many useless 2s in equations and the equations that do rely on other values of Pi are completely fine.

Pi really is half of something for almost all use-cases.
It has its uses, but a fundamental value it ain't.

Re:It was something I always wondered... (0)

Anonymous Coward | more than 2 years ago | (#39329941)

For the highschool math that you remember. It is not "half of something" for all uses.
Someone else posted http://www.thepimanifesto.com/ [thepimanifesto.com]
Have a look.

end the debate (1)

ticktickboom (1054594) | more than 2 years ago | (#39329629)

start using 366 degrees for a circle, its a lot more precise, and makes pi solvable

Re:end the debate (1)

DetriusXii (632162) | more than 2 years ago | (#39329793)

start using 366 degrees for a circle, its a lot more precise, and makes pi solvable

Degrees are an arbitrary unit to divide a circle. It has nothing to do with PI. Units of degrees break when doing calculus because the unit isn't a natural unit to put into cosines and sines. Sines and cosines (and e^ix) take as arguments units of numbers. I still don't get what you mean by making PI solvable. There's nothing to solve about PI. It just happens to be the number that relates Diameter and circumference of a circle.

Re:end the debate (1)

sconeu (64226) | more than 2 years ago | (#39330013)

No, there should be 365.2422 degrees in a circle! That way, the Earth moves 1 degree per day!!!

Niether side is convincing (5, Funny)

sdhankin (213671) | more than 2 years ago | (#39329685)

Both are irrational.

Tau of Pooh (1)

Oswald McWeany (2428506) | more than 2 years ago | (#39329811)

The problem with Tau is that it will always be associated with Pooh thanks to the book the "Tau of Pooh".

Pi day sounds way more appetizing than Pooh day. In the land of prunes, every day is a Pooh day.

Towel Day (0)

Anonymous Coward | more than 2 years ago | (#39329833)

I've always been more into Towel Day [towelday.org] myself.

Oh and obligatory... (2)

Oswald McWeany (2428506) | more than 2 years ago | (#39329871)

Oh and obligatory:

Taumorrow, Taumorrow, I love you, Taumorrow, you're only a day away......

I know it's not /.'s way, but.. (0)

Anonymous Coward | more than 2 years ago | (#39330033)

March 14 is Steak and Blowjob day. If we have to put up with Valentine's Day, we get our own day. But no. People want to be nerds and avoid getting laid..

It's nerd divided by zero (1)

gelfling (6534) | more than 2 years ago | (#39330039)

For sufficiently large values of nerd.

Area of a circle argues for pi (1)

mophab (137737) | more than 2 years ago | (#39330057)

Which is better?

Area = (pi) r^2

or

Area = (tau/2) r^2

It all depends on what problem you are trying to solve.
Just live with pi.

...hmmm (1)

Pirulo (621010) | more than 2 years ago | (#39330083)

Tau is twice as wrong!

Anyone going to bake a Pi-cake? (1)

knarfling (735361) | more than 2 years ago | (#39330089)

I recently saw an image of a Pi-Cake with the caption, "It's cake. But it's pi. But it's CAKE. But it's PI. BUT IT'S CAKE!!!"

After a little research, I even found a recipe for pi-cake. Pi-Cake [instructables.com]
While an irrational pursuit, it looks to be a tasty one. Anyone thinking about making one?

e^(pi i) = -1 (1)

buglista (1967502) | more than 2 years ago | (#39330109)

now, FUCK OFF.

yours,
a mathematician and coder, with frankly better things to worry about.

Double steak, double BJ day? (0)

Anonymous Coward | more than 2 years ago | (#39330117)

So, can I get two steaks and two BJs on Tau Day? If so, let's talk. Otherwise, I'll stick to pi.

They're both wrong. (1)

Barbara, not Barbie (721478) | more than 2 years ago | (#39330207)

the circle has been considered the most perfect of shapes

And yet, the circle needs a point to define the center, and an infinite number of points around the circumference to define the circle itself. The most perfect of shapes is a point. It is the basis for all other shapes, both in flatworld, in 3d space, and in space-time. Without the point, there would be no point (pun intended) to trying to define a circle either as pi or tau (where is your center to get your diameter or radius from, hmmmm?).

So, when is point day? Since you ask, you have not yet achieved enlightenment :-)

Math Nerds (0)

Anonymous Coward | more than 2 years ago | (#39330267)

Math nerds be gone! This is the domain of computer nerds!
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