Happy Tau Day

Forget about Pi Day, today we celebrate something twice as good: Tau Day. For far too long, Pi has been the bride and Tau has been the bridesmaid. As Michael Hartl points out in The Tau Manifesto, "Pi is a confusing and unnatural choice for the circle constant." He is giving a talk at the California Institute of Technology based on the Manifesto, with pie served at the end. "Twice as many as you might expect," he says.

Comments

really scraping the bottom of the barrel

[Anonymous Coward]

news for nerds, eh?

Re:really scraping the bottom of the barrel

[Anonymous Coward]

ha ha. You're not a nerd. ha ha!

Re:really scraping the bottom of the barrel

[thomasdz]

ha ha. You're not a nerd. ha ha!

shut up Nelson

Re:really scraping the bottom of the barrel

[yincrash]

There was a Pi Day post, so you can be discriminatory and not have a Tau Day post.

Re:really scraping the bottom of the barrel

[Roobles]

No, I wouldn't call this news for nerds. Because it's not news. But I do think it's relevant to nerds, especially those that take interest math and music.

It's creative. It's mathematical. It's something that a non-nerd would struggle to appreciate. It's even under idle. So what's the problem?

Re:really scraping the bottom of the barrel

[AmaDaden]

Yes. The idea of a mathematical notation that has been around for generations being replaced with something that makes more sense is something I would consider "News for nerds". While the idea has been spoken about before on slashdot and thus Tau it self is not news, Today being a day to promote it is news.

Re:really scraping the bottom of the barrel

[calmofthestorm]

Teach both sides.

Re:really scraping the bottom of the barrel

[bluefoxlucid]

We have working with half the radius of the circle or twice the circumference given its diameter. Radius makes little sense, and it's 1/2 diameter...

Re:really scraping the bottom of the barrel

[AmaDaden]

I know changing from Pi to Tau seems silly but it's not at all about radius vs diameter for calculating the circumference, It's about everything else that uses Pi. When equations that use Pi are compared to other similar equations that use other constants they are always off by a factor of 2 in some way. Tau fixes that in all cases I am aware of (If you know any it does not please post them). "The Tau Manifesto" link goes over this in detail. Tau is simply a more fundamental constant then PI.

Re:really scraping the bottom of the barrel

[vlm]

Teach both sides.

The lack of a constant between Pi day and Tau day proves that constants did not evolve on their own. Unless you can find a constant between Pi and Tau in the Holy Book of Knuth, or in the text of the Apocrypha/Art of Electronics, I must conclude that an intelligent designer created both Pi day and Tau day instead of a mere theory of slashdot dupe article evolution. Unfortunately the intelligent designer was not intelligent enough to make either day interesting enough for me to care, so sorry.

Re:really scraping the bottom of the barrel

[Anonymous Coward]

tau is fucking retarded. That's the problem.

Yeah, there are a few weak arguments to be made why 2*pi is a better choice for a circle constant than pi. Fine, argue. It's stupid, but I won't call you out for it.

Oh, hey, let's use a greek letter that is already used in many situations where the circle constant is used and define it to be our circle constant to cause ambiguity and confusion. What the fuck, people?!

Re:really scraping the bottom of the barrel

[koreaman]

Seriously? A few weak arguments? I see 2pi way, way more often than pi.

Re:really scraping the bottom of the barrel

[black soap]

makes more sense, except when calculating area. or volume. should we have separate constants, that are integer-ratio-multiples-of-pi, for each of those?

for a circle:
circumference=2*pi*Radius=tau*radius
area=pi*radius^2=0.5*tau*radius^2
for a sphere:
surface area=4*pi*Radius^2=2*tau*radius^2
volume=(4/3)*pi*radius^3= fuck it, why are you messing with pi?

do these people not realize that pi has applications beyond what they remember from basic geometry?

Re:really scraping the bottom of the barrel

[RuiFerreira]

There isn't but there should be. I'm writing the gamma manifesto where instead of e - the euler constant - we use gamma. For the obvious reasons, gamma=2e.

Re:really scraping the bottom of the barrel

[sexconker]

I know changing from Pi to Tau seems silly but it's not at all about radius vs diameter for calculating the circumference, It's about everything else that uses Pi. When equations that use Pi are compared to other similar equations that use other constants they are always off by a factor of 2 in some way. Tau fixes that in all cases I am aware of (If you know any it does not please post them). "The Tau Manifesto" link goes over this in detail. Tau is simply a more fundamental constant then PI.

Tau is retarded. There's no point to it. Having a trig function have a 2 or not doesn't make it more elegant. 2 Pi is a constant. Tau is a constant. They're identical.
The rallying cry of this stupid meta-nerd Tau bullshit is "Pi is wrong!". That's just complete horse shit.
The main argument is

In particular, since a circle is defined as the set of points a fixed distance—the radius—from a given point, a more natural definition for the circle constant uses r in place of D:

Who gives a shit? What about when you want to define the area (you know, "the set of points a fixed distance—the radius—from a given point")? Pi R^2 is more "elegant" than Tau/2 R^2. What about when you want to use trig functions? We should be using Pi/2 for those, not Pi, and not 2 Pi.

And why are we concerned with a circle anyway? We live in 3D space (at least, for now) and we should be dealing with 3D objects. What's the volume of a sphere? 4/3 Pi R^3? Fuck that! It should be Lambda R^3 so it's more elegant!! Pi is wrong! Lambda is 4/3 Pi!

The bottom line is that if you want to talk about "elegance", you should be defining your point collections as {L = , M = x}, where L is the locus defined in your native dimension, and M is the magnitude (end to end or center to end, I don't give a shit). 1D? Line segment. 2D? Circle. 3D? Sphere. 4D? Yo Momma.
Add a Phi if you want to define a circle in 3D space, or a line segment in 2D space. Add a Theta or some shit if you want line segments in 3D.

The entire argument for Tau is imbecilic. It reeks of "I got a problem wrong on a test because instead of actually understanding trig functions, I memorized them, and memorized them wrong." This is fucking "KB = 1000B" all over again - utter horseshit that morons will point to as an excuse when they fuck up. "See? I was right!" No bro, you were wrong. At least with this Tau horseshit we won't have marketing departments behind the push for detrimental ambiguity.

Use Tau all you fucking want. Just understand that no one else gives a shit, and no one will be teaching it in schools.

Re:really scraping the bottom of the barrel

[Goaway]

No, radius is the principal measurement of a circle, a sphere, a hypersphere, and so on. The diameter is the mathematically unnatural measurement. The diameter is used nowhere but in the relation of circumference to diameter. All other calculations use the radius, and factors of 2 pi.

Pi was chose as it was because it is more practical to physically measure the diameter than the radius. This does not make it a mathematically sound choice, however.

Re:really scraping the bottom of the barrel

[black soap]

we speak of a "radius of curvature" when describing curves other than circles. "diameter" presupposes a circle.
if you want to define the position of a circle, the simplest way is to give the coordinates of the center - and the radius.

Re:really scraping the bottom of the barrel

[AmaDaden]

For the area you're forgetting your calculus. Area calculations are basically summation equations and those always have a 0.5 in there. Table 3 of "The Tau Manifesto" shows several other such equations.This is a minor point that becomes a big deal. By lacking consistency across math what should be obvious and beautiful similarities become lost and hard to see.

Those other calculations are not any more difficult then they were before. Changing to Tau here is again a net benefit for mathematics.

Re:really scraping the bottom of the barrel

[AmaDaden]

Personally the argument for Tau has nothing to do with trig. Zero. Pi in Trig is harmless, it's once you start using Pi for everything else that it becomes ugly and clearly the wrong constant. Read "The Tau Manifesto", it goes over all the place that Pi is not as good as Tau.

Re:really scraping the bottom of the barrel

[black soap]

I am not forgetting my calculus. Teaching calculus payed for my liquor fund through college. I'm trying to avoid having to learn a second version.

Re:really scraping the bottom of the barrel

[AmaDaden]

I'm sorry but if switching to Tau requires you relearn calculus you have bigger problems then switching to Tau

Re:really scraping the bottom of the barrel

[Dr_Barnowl]

Having a trig function have a 2 or not doesn't make it more elegant.

Ok, let's go with one of the simplest trig functions around, converting angles.

With radians expressed in fractions of pi, a full circle is 2*pi radians.
With radians expressed in fractions of tau, a full circle is tau radians.

So half a circle angle.. is 1/2 tau radians. A quarter is 1/4 tau radians.

An eighth of a circle 1/4 pi radians. A quarter is 1/2 pi radians.

I know which looks more elegant to me...

Re:really scraping the bottom of the barrel

[black soap]

I already have Tau. It is spelled "2*pi"

I usually didn't call it "Tau," because that is often being used to represent other things. In mechanics, it often represents Torque. In electrical engineering, it is used for a time constant.

Is this the newest incarnation of the idiots who keep trying to redefine pi to make it easier to work with? They never did well with it in school, so now they want to do away with it, start their own club, and make everyone learn their way for a change?

Re:really scraping the bottom of the barrel

[2names]

Wouldn't "seeing 2Ï" be a subset of "seeing Ï?"

Re:really scraping the bottom of the barrel

[kshade]

What about not using greek letters in math at all? If a programmer would try to pull off that kind of stuff he'd be fired.

Re:really scraping the bottom of the barrel

[AmaDaden]

As an engineer I am aware of how over loaded Tau is at the moment. I agree that Tau is not the best choice here but that does not change that 2 Pi is not as elegant as using another symbol and is something we should consider replacing. Math would be clearer and simpler for future generations if Pi was replaced.

Re:really scraping the bottom of the barrel

[jojoba_oil]

Thar's a tau-day post every day, n' tau-morrow thar'll be posts too!

Re:really scraping the bottom of the barrel

[FrangoAssado]

There's no question that "The Tau Manifesto" makes valid points that tau makes more sense than pi in some settings.

Still, I'm a little astounded by all the people that treat this as some profound insight. "The Tau Manifesto" itself is written in a tongue-in-cheek way, and it fits: it's not meant to be taken too seriously. At least, I never thought it was. The examples are hand-picked to make tau look good, and even among them, some are not fully developed: if they were, the arguments would fall apart.

Take the example of the area of the circle. If you generalize for n dimensions, all the talk about comparing it to formulas in physics (uniform acceleration, potential energy, etc.) to justify the 1/2 factor (which would be an argument for using pi) disappears: the general formula doesn't favor either pi or tau, it has ugly constants with both of them (it could even be argued that it looks better with pi).

And what's the point of saying "Tau fixes that in all cases I am aware of (If you know any it does not please post them)"? Things like this might go well in discussions about religion, not math.

Re:really scraping the bottom of the barrel

[carpenoctem63141]

If future generations can't deal with multiplying a constant by 2, they probably shouldn't be doing math.

Re:really scraping the bottom of the barrel

[black soap]

Rearranging the formula for area so that it is consistent with several formulae for energy (as shown in table 3) seems to be more compelling an argument to the author than I find it. The author seems to make use of several exclamation points and rhetorical questions, which also tends not to impress me . Math would be no clearer after such a change, and even trying to make it happen will probably just lead to more confusion.

Re:really scraping the bottom of the barrel

[SharpFang]

Still, complex numbers arithmetics is inherently 2-dimensional.
And e^(value*tau) compared to e^(value*2pi) really helps once you include it in complicated expressions, where the "2" starts to crop up, getting squared, added, multiplied and so on.

Re:really scraping the bottom of the barrel

[AmaDaden]

I find that example very compelling. It was something that bothered me for awhile when I was learning math. It is a major formula created by doing an integral that looks different for no immediately clear reason. The reason, I eventually noticed on my own years ago, was Pi was a bad choice for a constant and this has been adjusted for by just using 2 Pi 90% of the time.

The article was written like that for the authors own amusement. See the FAQ section

Are you serious?
Of course. I mean, I’m having fun with this, and the tone is occasionally lighthearted, but there is a serious purpose.

Re:really scraping the bottom of the barrel

[AmaDaden]

By that logic nothing should ever be simplified or improved because "If you can't do it the way I did it you should not be doing it!"

Re:really scraping the bottom of the barrel

[FrangoAssado]

Yes, I never disagreed that sometimes it makes more sense to use tau. Still, I play a lot with complex arithmetic (by hand! [1]) when learning quantum computation. I've never had a single instance where absorbing the "2" into a constant (tau) would make things dramatically simpler.

The main point, though, is that people seem to make it a bigger deal about it than what it is. It's just a constant. Sometimes it makes more sense (in a "pure" sort of way) to use tau -- especially in really simple examples, it seems. Sometimes, it makes more sense to use pi. Most of the time, though, it doesn't really matter, since there are other constants involved either way. It seems that the benefits of using a single standard (pi is already established) seems to vastly outweigh the trouble of getting used to another constant.

[1] BTW, if anyone knows where I can find some easy-to-use free software that deals *symbolically* with complex matrices -- in particular, multiplying, inverting and calculating eigenvalues and eigenvectors, I'd LOVE hear about it. I mostly use Sage (it's what I ended up using after searching a bit a few years ago), but I end up doing a lot by hand because it seems to refuse to deal with complex numbers in any sensible way -- it doesn't like to keep constants like pi or sqrt(2), and replaces them with inexact floating point values. Mathematica seems to do the right thing -- is there some free software that does the same?

Re:really scraping the bottom of the barrel

[AmaDaden]

The general formula for a circle does not favor Pi or Tau but the general formula for finding an area for simple shapes does favor Tao. The formulas shown are compared not because they are all for the same area of study but because they are all derived the same way mathematically. In a very real sense, they are all the same formula just with different variables. Looked at this way the 1/2 belongs there, the math says so, it's Pi that messed it all up and got it canceled out. The area formula is a false positive in favor of Pi.

Personally I don't treat this as a profound insight because Pi felt wrong for a long time. It kept coming up as 2Pi in formulas and only very rarely did it stand on it's own. You can't show a person 2Pi a million times and expect them to still think that Pi with out the 2 is worth much. I can't speak for others but I'm guessing lots of other people felt the same and once they saw "The Tau Manifesto" they had that uneasy feeling finally justified. The math is much cleaner with Tau. That does not mean much if you want to just get work done but if you enjoy the beauty of math it's a big deal.

Actually that question does much better in talks of math. I am far more interested in being shown cases where I am clearly wrong by the numbers then cases where I am wrong because of some old book said so. I learn and improve by actively seeking out things I think are true that are actually wrong. So if you can give me a case where I am wrong in this I would be happy to see it.

Re:really scraping the bottom of the barrel

[FrangoAssado]

The general formula for a circle does not favor Pi or Tau but the general formula for finding an area for simple shapes does favor Tao.

I disagree. I don't think it "favors" tau or pi, I think the choice is arbitrary. Before you start thinking I'm an idiot, or simply trying to be difficult just to maintain the status quo, please read my whole explanation.

The example of calculating the area of the circle in The Tau Manifesto does an integral with the radius going from 0 to r. When dealing with a circle, if you think in terms of the radius (as opposed to the diameter), tau is more natural: this is unsurprising, since The Tau Manifesto itself defines it as tau=C/r. Obviously, when dealing of a circle, you think about the diameter (and not the radius), then pi is more natural: pi=C/d.

When you compare the integral (using the radius) with the other simple integrals from physics, you may get a sense of discovering an underlying pattern (in Table 3 (page 16) everything has the exact same formula structure) and all of a sudden everything seems to fit in place. It begins to look like it's obvious that you should choose to work with the radius, and not the diameter. Most of the feeling that tau is "simply better" or "more natural" seems to come from this realization (and other similar ones in the other examples in the Manifesto).

I claim that this is misleading, and it simply isn't true that "the general formula for finding an area for simple shapes does favor Tao". It just happens that, coincidentally, there's a simple way to calculate the area of the circle that integrates over the radius. But if you wanted to calculate the area of a square, or of a triangle, or, even better, some arbitrary shape, the simplest thing to do would NOT be to pick a point inside the shape and integrate over some "rings" (or whatever shape) while moving away from this point to the edge of the shape. Moreover, it is a coincidence that this way to calculate the area of the circle (integrating using the radius, which favours tau) works as beautifully as it does -- it doesn't look as good in any larger dimension (volume, etc.).

But that's just one example. There are many others, usually just silly or misleading in some other way. As for the claim that everywhere you see pi in a formula it's always multiplied by 2, that's just silly.

Still, I already said I agree that tau is better in some places. For example, e^(i*tau) looks more natural than e^(2*i*pi), for the exact same reason that sin(x)=sin(x+2*pi): in the "natural" definition of the trigonometrical functions, 2*pi is "one full circle back to the same point". But that seems to be the only real argument. It's been obvious for a very long time and it doesn't seem reason enough to justify a massive change in the way we write these things. Gratuitous incompatibility is bad!

Re:really scraping the bottom of the barrel

[AmaDaden]

While I still disagree with you on the area of a circle you make a good point. I still feel that there is a fundamental rule that is clearly visible in that group of formulas I and the author have not put together a good representation of it. Since I am an engineer and not a mathematician I don't think I will be able to correctly represent it by continuing so I will not bother to go in to it further.

I honestly can not remember many places were Pi was on it's own. If you can please do mention them.

A major part of the point of what I guess you could call the 'Tau movement' is that it is not at all incompatible. That's why (and again the Tao manifesto covers this) they are suggesting using Tau and not changing the value of Pi. You would simply be introducing a new constant that everyone could recognize as 2 Pi. Books could also have the two different versions of the formulas on the same page of their text books and they should be able to function just fine.

To be honest I actually do have one problem with the idea, Tau is already heavily used in other areas (it looks to much like a T to be ignored), another less used Greek letter should be chosen instead.

Re:really scraping the bottom of the barrel

[zmughal]

You should try out Maxima. I think it may be one of the backends for Sage, but if you use it directly you can program the symbolic engine to simplify how ever you want.

Re:really scraping the bottom of the barrel

[FrangoAssado]

Whoa, thank you very much! At first look, it seems be exactly what I need! Now it seems I'll have to get used to Maxima's way of doing things. :)

And indeed, Maxima is even included with Sage, although I don't know what exactly Sage uses it for...

Re:really scraping the bottom of the barrel

[stridebird]

Rant of the year. Chapeau monsieur!

Mmmm pi

[Goose In Orbit]

As Weebl and Bob might say...

"Twice as many as you might expect"?

[Anonymous Coward]

I would expect 2 Pi.

Oh come on.

[Anonymous Coward]

This merits publishing?

Fuck that, I've created Upsilon!

[elrous0]

It's 4*Pi, which makes it TWICE as kick-ass as Tau!

Re:Fuck that, I've created Upsilon!

[Anonymous Coward]

Actually, Tau makes more sense than Pi or your Upsilon.

Pi = c/d or Pi = c/2r -- Which means it's a ratio between the circumference and the diameter, but radians are based on the radius, so a full circle is 2Pi radians.
Tau = c/r -- Which makes life a lot easier, because then the circle is Tau radians.

So what? Well, that means when graphing trigonometric functions becomes a whole lot easier:
See

Re:Fuck that, I've created Upsilon!

[vlm]

Actually, Tau makes more sense than Pi or your Upsilon.

Pi = c/d or Pi = c/2r -- Which means it's a ratio between the circumference and the diameter, but radians are based on the radius, so a full circle is 2Pi radians.
Tau = c/r -- Which makes life a lot easier, because then the circle is Tau radians.

So what? Well, that means when graphing trigonometric functions becomes a whole lot easier:
See

Tau makes it harder to teach. The stereotypical constructive geometric way to teach Pi is to use a string anchored at the center and a pencil at the other end to draw the circle using the geometric definition of what a circle is, and then figure the ratio of the string to the drawing. Tau... That's not obvious how to teach using constructive geometry and mathematical manipulatives.

Re:Fuck that, I've created Upsilon!

[heathen_01]

Tau makes it harder to teach. The stereotypical constructive geometric way to teach Pi is to use a string anchored at the center and a pencil at the other end to draw the circle using the geometric definition of what a circle is, and then figure the ratio of the string to the drawing. Tau... That's not obvious how to teach using constructive geometry and mathematical manipulatives.

I don't understand your point. The length of the string must is equal to the radius but what is the drawing equal to, the circumference? If so then you have drawing/string = C/r = 2Pi = Tau.

Re:Fuck that, I've created Upsilon!

[vlm]

I don't understand your point.

That's because I'm too spaced out this early in the morning. Yeah, I guess I'm now converted to the Tau side, too.

Re:Fuck that, I've created Upsilon!

[Anonymous Coward]

Well good luck celebrating 12/56. It's not more kick-ass if it can't be celebrated as a holiday, everyone knows that...

Re:Fuck that, I've created Upsilon!

[interkin3tic]

Ah, you went the other direction with that. I invented "Pie day." It has less to do with numbers or greek letters and more to do with pastry and delicious.

Re:Fuck that, I've created Upsilon!

[drb226]

Pi * r^2. Tau that.

Re:Fuck that, I've created Upsilon!

[Raenex]

Check out what it does to Euler's Identity. That and the straightforward definition of radians has made me a convert, too.

Re:Fuck that, I've created Upsilon!

[geekoid]

Pie day is everyday.

mmm pie.

Re:Fuck that, I've created Upsilon!

[elrous0]

I could get behind that.

Re:Fuck that, I've created Upsilon!

[Kompressor]

1/2Tau * r^2.

Done. Next?

Re:Fuck that, I've created Upsilon!

[Anonymous Coward]

Area of a circle with the radius r = tau*r^2 / 2

This is analogous to things like:

Kinetic energy = m*v^2 / 2
Distance travelled under constant accelleration = a*t^2 / 2 ... which also involve areas and integration.

Yes, in the special case of calculating circle area, you have to add a factor 1/2 when using tau rather than pi, but only because pi "hides" the factor 1/2 as in pi = tau / 2. Weigh this against the myriad cases where substituting tau for pi makes the formula simpler removing numerical constant, and tau still wins.

Re:Fuck that, I've created Upsilon!

[rmstar]

Check out what it does to Euler's Identity. That and the straightforward definition of radians has made me a convert, too.

Well, not me. Frankly, I think this is a completely superfluous point to waste brains in. The inconvenient incompatibility with the sizeable literature corpus absolutely dwarfs any of the incredibly marginal advantages this tau idea might have. I think this is simply a campaign by someone who wants to draw attention to himself (i.e. a troll)

Re:Fuck that, I've created Upsilon!

[Anonymous Coward]

Awesome!

Re:Fuck that, I've created Upsilon!

[Anonymous Coward]

Let us derive for a moment the formula for the area of a circle, by summing an infinite amount of infenitessimally small triangles.

These vertices will all have the "top" point in the middle of the circle, and the base of the triangle will be along the approximated circumference of the circle.

The height of the triangle will always be r (of course, since the length from the center of the circle to the base of the infenitessimally small triangle will be equal to the radius).

The width of the base of the triangle will be (tau*r)/n - because tau*r is the circumference of the circle, and divide that circumference into n infenitesimally small pieces.

The area of each triangle will therefore be (1/2) * (tau*r/n) * r - where the 1/2 comes from the fact that we're calculating the area of a triangle, which is half the area of a square with the same height and width.

And then we multiply by n, or the infinite amount of triangles.

So we get the expression:

Area for a circle of the radius r = lim[n->inf] n*(1/2)*(tau*r/n)*r

As we simplify this we get tau*r^2/2 (the n's cancel out).

So the 1/2 comes naturally from the fact that the area of a circle is naturally calculated by summing an infinite amount of triangles together. Using pi to calculate the area of a circle as in pi*r^2 hides this beautiful fact.

Re:Fuck that, I've created Upsilon!

[drb226]

4/3 * pi * r^3

Re:Fuck that, I've created Upsilon!

[jimshatt]

Ehrm, 2/3 * pi * r^3, duh.

Re:Fuck that, I've created Upsilon!

[jimshatt]

Wow. Thank you for making me a convert!

Re:Fuck that, I've created Upsilon!

[onefineline]

2/3 * tau * r^3 ?

Re:Fuck that, I've created Upsilon!

[jimshatt]

Yes, dammit, I can't even type anymore! Thanks for the correction.

Re:Fuck that, I've created Upsilon!

[Morphine007]

Change and progress in academia!? ... Preposterous!!...

Re:Fuck that, I've created Upsilon!

[rmstar]

Change and progress in academia!? ... Preposterous!!...

Morphine007 actually understanding anything? No way!!...

arg

[Anonymous Coward]

oh god, this argument again...fuck my life.

Re:arg

[Anonymous Coward]

we'll go with the tau if you drop the kibibytes :P

Re:arg

[hedwards]

Fo' shizzle.

Re:arg

[treeves]

Fahrenheit.

Re:arg

[Kompressor]

He sneezed?

Re:arg

[treeves]

No, he drove somewhere.

2x the pies

[Bob the Super Hamste]

I guess I will have to go down to Bakers Square and get 2 pies today.

wrong tau

[Anonymous Coward]

For the greater good!

Re:wrong tau

[bsharp8256]

Haha my first thought too.

Re:wrong tau

[xmousex]

the whole reason i clicked it too

fucking math fags

also tomorrow is kroot day, cannibal feast!

Re:wrong tau

[Aquaseafoam]

Filthy Heretics.

Tau pffft...

[Anonymous Coward]

I have never heard "Shut your Tau hole!",and yet I hear "Shut your PI hole!" almost every day.

Re:Tau pffft...

[tepples]

I have never heard "Shut your Tau hole!"

That's because the Tau that can be shut is not the true Tau.

Re:Tau pffft...

[taiwanjohn]

Thanks man, it's been a long day, and that gave me a really good laugh. ;-)

Dup!

[Anonymous Coward]

Wasn't this posted last year?!? I mean come on editors!

Re:Dup!

[hedwards]

I see you're protesting Euler's main number.

Re:Dup!

[Anonymous Coward]

Absolutely, I mean e is so unnatural. I've always preferred to use schwa which is e ^ i. Euler's formula would then become

schwa ^ tau = 1

which, obviously, is perfection.

Always show your work

[Maximum Prophet]

Back in 7th grade the teacher wanted us to show our work. Most of the time I could figure out the stuff in my head, so I didn't want to do that. In order to freak out the teacher, I memorized the multiplication table of (single digit) * 3.14

After that I could write stuff like 67*pi = 188.40 + 21.98 = 210.38 (vertically)

The teacher never commented on showing my work after that...

Re:Always show your work

[Anonymous Coward]

Why did you need to memorize it? I just ran through them in my head really quickly.

Re:Always show your work

[bluefoxlucid]

He's not Japanese and hasn't trained with a Soroban.

Re:Always show your work

[geekoid]

Then you teacher failed. Showing your work is about knowing the procedure to do something.

Even the dimmest child can look at: 4 * X = 8 and KNOW X=2. But the real lesson is showing the work so when it's not that easy you can get a correct answer.
You use an easy example so when they finish going through the correct steps they can know they did it correctly.

Re:Always show your work

[AikonMGB]

One of the worst things you can do to a student that truly understands the material is to drag them down and force them to do what they consider menial tasks. It is a fine line, because I agree that it is important that students learn how to work through more complicated problems. However, when someone has already demonstrated their ability and is effectively doing homework and writing tests simply to "jump through the hoops", you can seriously cripple their interest in pursuing the field entirely and drive them away.

I know that it is a difficult task in today's school system, but the correct approach is to challenge the student and engage them mentally.

Aikon-

Re:Always show your work

[AikonMGB]

Now for the anecdote part relating how a "one-size-fits-all" education scheme doesn't work in practice:

In elementary school, my brother's teacher would give the class spelling quizzes. He scored 100% on the first quiz. The second quiz rolled around and he scored 100% again. He was distraught because many of his colleagues had gotten stickers on their returned quizzes as rewards, and yet he had gotten nothing. The teacher's explanation was that the rewards were for improvement on the quizzes -- if you did better than last time, you got a sticker.

His response was to intentionally fail the subsequent quiz, and then slowly build up his score to 100%, and then restart the process. The teacher was concerned about his inconsistent spelling skills and thought he might have problems with distraction; my parents understood what had happened immediately.

When you reduce education to the lowest common denominator, you remove any chance for the gifted, the skilled, the interested, and the excited students to excel at their studies.

Aikon-

Re:Always show your work

[Anonymous Coward]

One of the worst things you can do to a student that truly understands the material...

... is to molest her. You creepy child molester.
On the other hand, one of the best things you can do to a student that truly understands the material is to molest him. But only if you're a hot chick. You creepy child molester. rawr!

Re:Always show your work

[Roger W Moore]

One of the worst things you can do to a student that truly understands the material is to drag them down and force them to do what they consider menial tasks.

Exactly. What the teacher should have done is give them a question that they cannot do in their heads. If they can do 67pi then how about 67e or 123*sqrt(3) etc. That does not drag them down but does teach them that, smart as they are, there are always more difficult problems out there so they should not get too cocky.

Re:Always show your work

[sdguero]

Your not special.

Re:Always show your work

[NeutronCowboy]

Showing your work to me was never a benefit for me. Grading homework, I actually much preferred the people who just put down the answer. Is it right? Full points. Is it wrong? Zero points. I could whip through a 20 part homework in about 30 seconds flat. When they showed their work, I actually had to follow through and check for mistakes. It was 100% upside for the students: if they made a boneheaded mistake (64 bitshifted twice to the right = 256), they got nearly full points. Showing your work meant that you got at least 50% of the points, unless you totally, completely screwed up basic principles.

Not to mention it's a valuable skill later in life: very few people just take you at your word, and you shouldn't take anyone at their word as well. Make them show you their work. Proper presentation of reasoning is at least as valuable in convincing people as the position itself.

Re:Always show your work

[Archtech]

Why did you need to memorize it? I just ran through them in my head really quickly.

John von Neumann? We thought you were dead!

Re:Always show your work

[linuxwolf69]

I did 4 years of high school math (from Geometry - Calculus) without doing any homework. I had a knack for understanding the material and made straight A's. Fortunately, my teachers and I reached an understanding that allowed me to not do the homework. I absolutely HATED the repetition of doing the same problem 20 times with different numbers.

Re:Always show your work

[Anonymous Coward]

Actually, it's in knowing a particular method - not knowing how to do it. While showing the method is important to a degree, to a much larger degree it is used to ensure only a single method that happen's to be a particular teacher's favorite is learned and tends to stray away from others, ultimately hindering the student.

Re:Always show your work

[treeves]

Ramanujan lives!

Re:Always show your work

[Anonymous Coward]

ha I'm watching that 30 rock right now :)

Re:Always show your work

[Anonymous Coward]

I bet you had no friends

Re:Always show your work

[jfengel]

Then your teacher failed at teaching you about significant figures. 67*pi=210.49, not 210.38. The difference is small, but you were only working with 3 significant figures of pi, so everything past the decimal point is going to be random. It just so happens that the next decimal places are small (.00159), which helps on the next digit, but the final digit is pretty much entirely junk.

210 is good enough for most purposes, for the same reason that 3.14 is good enough for most purposes, and the teacher should have marked extra digits as wrong. Honestly, it was easier to leave it at 67*pi, and more correct.

Re:Always show your work

[Just Some Guy]

And my teacher taught my that "seperate" is a verb, while "separate" is an adjective. She also taught the hard-and-fast "i before e" rule and caused me to lose a spelling bee, ironically by misspelling "forfeit".

I'll believe pretty much any crazy story you tell me about dumb ways of teaching spelling.

Re:Always show your work

[wolrahnaes]

Then you teacher failed. Showing your work is about knowing the procedure to do something.

Then once you've showed it they should fuck off and let you just do mental math.

I absolutely despised math teachers who enforced showing of work. Pretty much everything done in a math class below the high school level I could do in my head nearly instantly. Writing out the whole process was a waste of 30-60 seconds per question. On a long test that could be half the class period where I could be reading rather than writing out how I managed to figure out that 13 * 24 = 312.

I understand that it is useful both as a teaching aid (to see where the student got it wrong) and as a deterrent to cheating (harder to copy and of course calculators don't tell you how they got there), but that still didn't mean it should be used without exception. If the student can prove they know the material, let them stop having to prove it every damn time.

Re:Always show your work

[the phantom]

That's only because she didn't teach you the entire I before E rule: "I before E, except after C, and when sounded as A as in neighbor and weight, and remember that neither weird foreigner seizes leisure at its height." (That was the poem/rule/whatever that my mother had to learn in elementary school in the 50s.)

;)

Re:Always show your work

[the phantom]

That is my general take on things. I tell my students that they can show as much or as little work as they like. If they get the right answer, great---they get full points.* If they get it wrong, they get only as much credit as their work justifies.

Of course, I still encourage them to show as much of their work as possible. I've done a fair of math in my 30 years (not as much as some, but quite a bit more than most). I have a bachelors in the subject, am certified and have been employed as a high school mathematics instructor, and am currently working on a graduate degree in the field and teaching algebra to pay for it. I say this not to brag, but merely to explain that I have some experience with computation. I can do most of the required computations in my head, and I generally don't type up all of my work when turning in papers. I still write it all out on my whiteboard or scratch paper when I am working through a problem for the first time---this makes it easier to follow my own line of thinking, and easier to find my own mistakes.

* That isn't quite true---if a student gives me a correct answer but shows incorrect work, they will almost always lose a few points on that question. Students need to convince me that they have mastered the skills that I require them to master---if they show me incorrect work, then I am unconvinced. That being said, in most cases where students give right answers and poor work, it is because they are copying off of a neighbor, which can be easily verified.

Re:Always show your work

[Just Some Guy]

Which would still "forfeit" (pronounced "for-fit", at least in my region).

Re:Always show your work

[the phantom]

Indeed. There are other exceptions, too. "Their," for instance, depending on how liberally you take the second clause.

Re:Always show your work

[Anonymous Coward]

Provide an example. No, I'm serious. I want you to give a problem where the answer is instantly known and then a problem, in the same form, where the answer isn't as immediately clear.

Re:Always show your work

[Anonymous Coward]

Your not special.

You, on the other hand....

Re:Always show your work

[jodosh]

I always learned the Brian Regan rule: ""I before E, except after C, and when sounded as A as in neighbor and weight, and weekends, and holidays, and all throughout May, because you'll always be wrong no matter what you say."

Re:Always show your work

[metamatic]

One of the worst things you can do to a student that truly understands the material is to drag them down and force them to do what they consider menial tasks.

But shouldn't we be getting them ready for adult life and the world of work?

Re:Always show your work

[AikonMGB]

Gah, thank you for shattering my carefully constructed bubble of faith in humanity for the day =/

Re:Always show your work

[Anonymous Coward]

You use an easy example so when they finish going through the correct steps they can know they did it correctly.

This is the BS that pisses off everyone that actually can handle mental math. Problems should be chosen carefully so that the answer must be done by the specified method. If an easier method is available, it will teach kids that math class is where you learn redundant algorithms.

My favorite example is a problem from calc 1. My professor wanted us to solve for the height of a lamp post. I have no idea how we were supposed to do it because we were given the distance from the post on the ground and a look angle to the top . . . Anyways I got the right answer and a stern talking to, about following instructions

Re:Always show your work

[Subm]

I was thinking about correcting Maximum Prophet, but held back. If we're correcting each other, 67*pi is not 210.49 or 210.38. It's a transcendental number. It's a slippery slope if we slack on meaning of equals signs.

Memorizing 3.14 tables is memorizing something different than pi.

Back to the topic of tau day, I found the argument that tau makes a better circle constant than pi compelling. I got a PhD in physics and dealt with more than my share of 2*pis.

Re:Always show your work

[jfengel]

You get a lot of 2pis when you compute circumferences, but you would end up with just as many tau/4 when computing areas with diameters.

No skin off my nose either way.

Re:Always show your work

[tehcyder]

One of the worst things you can do to a student that truly understands the material is to drag them down and force them to do what they consider menial tasks. It is a fine line, because I agree that it is important that students learn how to work through more complicated problems. However, when someone has already demonstrated their ability and is effectively doing homework and writing tests simply to "jump through the hoops", you can seriously cripple their interest in pursuing the field entirely and drive them away.

I know that it is a difficult task in today's school system, but the correct approach is to challenge the student and engage them mentally.

Aikon-

Oh blah blah blah another misunderstood slashdot genius who was so clever at school he failed all his exams deliberately because they weren't challenging enough.

Re:Always show your work

[tehcyder]

That's only because she didn't teach you the entire I before E rule: "I before E, except after C, and when sounded as A as in neighbor and weight, and remember that neither weird foreigner seizes leisure at its height." (That was the poem/rule/whatever that my mother had to learn in elementary school in the 50s.)

;)

It's much easier just to learn the few exceptions to the rule of "i before e except after c" rather than that frankly ridiculous non-mnemonic. There's no point in trying to pin English spelling down to a few rules, there are pretty much always exceptions to everything.

Re:Always show your work

[tehcyder]

One of the worst things you can do to a student that truly understands the material is to drag them down and force them to do what they consider menial tasks.

Exactly. What the teacher should have done is give them a question that they cannot do in their heads. If they can do 67pi then how about 67e or 123*sqrt(3) etc. That does not drag them down but does teach them that, smart as they are, there are always more difficult problems out there so they should not get too cocky.

Hooray, someone speaking sense about educating the hordes of slashdot self-proclaimed geniuses.

Re:Always show your work

[tehcyder]

I did 4 years of high school math (from Geometry - Calculus) without doing any homework. I had a knack for understanding the material and made straight A's. Fortunately, my teachers and I reached an understanding that allowed me to not do the homework. I absolutely HATED the repetition of doing the same problem 20 times with different numbers.

I bet you're one of those people who hates documenting their work too.

Re:Always show your work

[tehcyder]

Gah, thank you for shattering my carefully constructed bubble of faith in humanity for the day =/

It's called facing reality. Once you leave home, life does not consist of being praised by others for being clever.

Re:Always show your work

[tehcyder]

Pretty much everything done in a math class below the high school level I could do in my head nearly instantly

Just maybe the teachers were preparing you for high school and higher level maths. Education isn't just about showing how fucking clever you are to teachers, it's accepting that there are strategies and techniques that, once ingrained, allow you to learn better in the long run.

But, obviously, you're such a fucking genius you still do everything in your head, right?

Re:Always show your work

[linuxwolf69]

Yeh mostly. Funny thing is that I could do complicated problems all day long, and if I got anything wrong, it was a simple addition or subtraction error. I didn't like showing work, but definitely found value in it when I was taking Calculus.

Re:Always show your work

[wolrahnaes]

Just maybe the teachers were preparing you for high school and higher level maths. Education isn't just about showing how fucking clever you are to teachers, it's accepting that there are strategies and techniques that, once ingrained, allow you to learn better in the long run.

Ok, so I did it once, I know how to do it, why do I have to keep doing it on stuff I don't need it for? When I got to the harder math I couldn't do entirely in my head, guess what? I wrote it out!

But, obviously, you're such a fucking genius you still do everything in your head, right?

Nope, I use a calculator and write down intermediate results as necessary, which makes sense. You apparently missed the entire point, which was not to say that it's always pointless but that forcing a student to do it in situations where they don't need to only results in a pissed off student. "the phantom" above got it, what's so hard for you?

Re:Always show your work

[the phantom]

I agree that the "non-mnemonic" is ridiculous, but I don't see how memorizing it is any different than learning (i.e. memorizing) the few exceptions. If you really care about memorizing that shit (rather than relying upon spell check, which I do for most things), then what is wrong with the above?

Re:Always show your work

[Urkki]

Even the dimmest child can look at: 4 * X = 8 and KNOW X=2.

This was sarcasm, right?

Re:Always show your work

[Aldenissin]

I whole heartedly agree. As Mr. Miyagi (The Karate Kid) said, "No such thing as bad student, only bad teacher."

A similar incident happened with myself. The teacher wanted me to write in cursive. I didn't want to. Then after a few tests she said my h looked like a k. There was only like a month and a half and me and Chasity both had a star for every week for getting a 100% on the weekly spelling test. I knew she wasn't going to miss a word going forward, so I didn't even try. I never did reclaim the same interest in anything related to English with the same gusto. There were several times I was not encouraged in school. But this article helps me see an answer to this problem.

They've got a point

[LordNacho]

Angles: 2Pi in a full circle? Somehow it's more satisfying if the proportion of a circle were between 0 and 1: xTau. So half a circle would be (1/2)Tau, not the whole-looking 1Pi.

If you look at various "important" equations, you often end up seeing 2Pi in there. Gaussian, Riemann, Fourier. Another one: h/2Pi, h being Planck's constant. Why not make 2Pi the constant?

Even Pi*r^2 is more appropriate as (Tau/2)r^2, if you compare with (1/2)mv^2.

I have to admit I was not violently emotional when I read the argument though.

Re:They've got a point

[Anonymous Coward]

Yes, but e^(i*Pi)+1=0
Overrules pretty much everything.

Re:They've got a point

[Anonymous Coward]

Why call it tau? Couldn't you call it, say, two-pi, and denote it with a symbol that looks like a 2 followed by pi? Then for half a circle you'd have (1/2)(two-pi).

Re:They've got a point

[Daniel_Staal]

e^(i*Tau) = 1

Is that not as good or better?

Re:They've got a point

[AlecC]

Agreed. This is just too elegant to throw away. Did not deserve to be modded down.

Re:They've got a point

[Anonymous Coward]

Can't we have both?

Re:They've got a point

[adisakp]

Yes, but e^(i*Pi)+1=0 Overrules pretty much everything.

The whole idea of Tau is for people who are too stupid to multiply by 2.

Throwing in e (the irrational number whose powers are the inverse of natural logarithms) and i (the imaginary square root of negative one) is gonna confuse them even more than taking Sara Palin to a book reading club.

Re:They've got a point

[Lord Lode]

Or if you want the constant 0 in it too, e^(i*Tau) - 1 = 0 :)

Re:They've got a point

[As_I_Please]

e^(i*tau) - 1 = 0

Re:They've got a point

[Anonymous Coward]

or as the tau manifesto suggests (that no one here as appeared to read), it's already there: e(i*tau) = 1 + 0, and no rearranging is needed.

Re:They've got a point

[LordNacho]

e^(i*Tau)=1+0

Re:They've got a point

[LordNacho]

RTFA, tauday.com. Figure 1.

Looks a bit confusing to me though.

Re:They've got a point

[heathen_01]

Its elegent in a weird twisted way, kind of like the scream. The "+1=0" is just a nasty hack to hide the fact that the equation equals -1.

Re:They've got a point

[Hythlodaeus]

RTFA e^(i*tau)=1

Re:They've got a point

[RyuuzakiTetsuya]

I think it's a false dichotomy to say you have to have one or the other.

Yes, calculating circles, cosines, etc, with Tau is going to be way easier than using 2Pi, but, for most non-math types, I can't imagine them needing that kind of distinction.

Plus additional greek letters always look cool.

Re:They've got a point

[Anonymous Coward]

Not quite, actually. By adding "+1=0", you manage to relate 5 pretty fundamental and independent numbers using 4 also fundamental operations (addition, multiplication, exponents, and equality). It basically, explicitly and implicitly, relates nearly every major concept developed by mathematicians in calculus, algebra, and geometry for some 3 thousand years. All in one small package.

Re:They've got a point

[heathen_01]

Sure, but you get the same thing using Tau, only you don't have to use the ugly hack.

Re:They've got a point

[Ken_g6]

Yes, but e^(i*Pi)+1=0
Overrules pretty much everything.

On the contrary, when you do e^(i*Pi)=-1, everything's upside down and backwards. Any point on the complex plane times e^(i*Pi) is rotated through a half-turn.

It's only when we do e^(i*Tau)=1 that everything comes full circle. I never really understood Euler's identity until I saw that.

Re:They've got a point

[Twinbee]

And why not scrap even Tau and have just 0-1 for a full circle? Yes I know the advantages of radians, but I've always found it useful to use cycles/revolutions for any trigonometric work. I'm amazed that it's not in more common use. With calculators, you get radians and degrees, but never cycles.

Re:They've got a point

[Anonymous Coward]

There's an elegance to e^(i*pi)+1 = 0 though that tau solutions just can't match.

First, the equation equals zero. That's just flat out natural
Second, the function naturally includes addition and multiplication. Subtraction is a messy hack of addition; are you subtracting one or adding negative one? Adding one, while pedants can say you're 'subtracting negative one,' is graceful and simple.

Re:They've got a point

[blueg3]

No, it's for people who are too lazy to multiply by 2. Consider that physicists have two constants for the same physical constant -- h and hbar -- because tracking the 2*pi factors is a pain. (For that matter, tracking the 2's with pi is also a pain. It's not really intuitive to look at 4*pi^3 and realize that in this case, that's because it's (1/2)*(8*pi^3).)

Re:They've got a point

[Volante3192]

You lose the addition and the zero, though. If ANYTHING in math can be considered fundamental, it's + and 0, along with 1.

Everything else is gravy.

Simplifying the equation loses the elegance it has. Also, tacking "+ 0" to the end of the tau version is an uglier hack than "+1 = 0"...when do you ever regularly add zero.

Re:They've got a point

[Lord Lode]

Replace the + by a - and the pi by a tau and the equation equals zero too.

The 1 + 0 thing of the tau manifesto looks weird. I think the one with the - is nicer.

By the way, I find e^(i*tau) = 1 to be pretty elegant as well! It's like, we take e and 2pi, mix a complex number in the bunch, raise it to each others power, and instead of being some number with lots of decimals, it's one!

Re:They've got a point

[Volante3192]

You lose the concepts of addition and zero in that.

The elegance of e^(i*pi)+1=0 is that it includes addition, multiplication, exponents, e, i, pi, 0, 1 and equality.
Basically, everything that forms the foundations of math is included. You exclude zero and addition, well, who cares if you're using pi, tau, lambda or cheese whiz?

Re:They've got a point

[heathen_01]

Simplifying the equation loses the elegance it has. Also, tacking "+ 0" to the end of the tau version is an uglier hack than "+1 = 0"...when do you ever regularly add zero.

I'm not happy with making an equation more complex and harder to understand just so that you can gain an addition and a zero. Using tau you can explain the equation as:

A rotation by one turn is 1.

Using Pi, the explanation would be:

A rotation by 1/2 a turn is -1.

Whatever happened to simple = elegant?

Re:They've got a point

[Anonymous Coward]

Simplifying the equation loses the elegance it has

⦠I hate math nerds.

Re:They've got a point

[rwa2]

Yeah, the "+ 0" looks kinda weird in an equation, but it's just the computation of the more useful
  e^(i*tau) = cos(tau) + i*sin(tau)

Re:They've got a point

[WNight]

But what does -1 mean? Why are you ignoring it by adding 1 to it? Why does using Tau produce 1? Do you understand the formula at all or are you just scoring it based on aesthetics?

Re:They've got a point

[Anonymous Coward]

Er...so you think mathematicians should use PI instead of TAU, just to make one (not particularly useful) equation more complicated?

I was skeptical at first, but now I agree that TAU is better because it simplifies a huge number of equations, makes the structure of other equations more obvious, and makes angle measurement in radians more intuitive. The choice of PI over TAU was a minor mistake that mathematicians made many centuries ago. Just a minor mistake though. If it were a big mistake they would have corrected it at some point, but instead the convention stuck.

Of course it's too late now -- we can't do a "find and replace" in all the text books and papers in the world, let alone people's brains.

Re:They've got a point

[Anonymous Coward]

The moment I realised tau was the way forward was an epiphany for me. I was working on a very large block of scientific code, and I mused with the idea of changing to tau. When I looked through the code I had written, every single instance of the constant pi was preceded with a 2*.

Re:They've got a point

[Volante3192]

...are you just scoring it based on aesthetics?

Yes.
If I wanted to simplify the equation, I could just boil it all down to "1=1" and who gives a toss? That's what an equation is. Left side equals right side. No more, no less.

Using pi, you can see the entire foundation of mathematics. With tau, it's there...but not quite. Like cutting the background out of Gainsborough's The Blue Boy. The portrait remains but you lose depth and contrast. You might not notice the background looking at the portrait, but you still feel its presence.

Equations are equations. Use them once, when you need them, and then they fade away.
y=4x+7, [ ( -9 (+/-) ( 81 - 4*1*5 ) ^.5 ) / 2 ] = j , f=ma.

e^(i*pi)+1=0 , though, is art.

Re:They've got a point

[Anonymous Coward]

Which is cooler/more useful?

e^i=1
e^i=-1

Re:They've got a point

[metamatic]

Another one: h/2Pi, h being Planck's constant.

Well, that brings us on to Planck Units. If we're going to change things to make the formulae easier, then it seems pretty clear that the universe has a set of much more natural units.

Pick your unit of length so that = 1, c = 1, G = 1, and so on. The equations of physics get a lot easier. (Particularly relativity with c being 1.)

Of course, there's the minor problem that your speed limit signs on roads have to be labeled 1.044×10^-7 (in planck lengths per unit planck time). But it's hardly physics' fault that everyday quantities are so inconveniently sized compared to the universe..

Re:They've got a point

[adisakp]

No, it's for people who are too lazy to multiply by 2. Consider that physicists have two constants for the same physical constant -- h and hbar -- because tracking the 2*pi factors is a pain. (For that matter, tracking the 2's with pi is also a pain. It's not really intuitive to look at 4*pi^3 and realize that in this case, that's because it's (1/2)*(8*pi^3).)

Then why not just write it as (2pi) ? For example, ( (2pi) ^3) / 2 rather than (1/2)*(8*pi^3) is as simple as Tau. Anytime you integrate or differentiate or go through powers or actually do *ANY* math with pi times any constant, you're going to be getting new constants anyhow. I doubt constant tracking is really all that hard and if you're too lazy to multiply by 2, you're probably going to be too lazy to explain that what your overloaded symbol is.

And tau is no better. What are we gonna do, teach that the area of a circle is tau/2*r^2 ?? You're just pushing laziness of constant from one group of equations to another. It's a lot of nonsense work with zero sum gain -- any perceived increase in efficiency by not having to multiply by two is gonna get cancelled out by having to divide by two or keep track of two symbolic irrational constants.

Re:They've got a point

[Anonymous Coward]

Just writing it as (2pi) in all expressions would accomplish practically the same thing, yes. Except it's many more key/pen strokes to write it that way. And you'd have to have a special rule for when you simplify expressions to always express everything in terms of 2*pi rather than just one constant. You'd have to simplify pi/3 as 2*pi/6 for example. Which actually makes a lot of sense since pi/3 = 2*pi/6 = tau/6 = 1/6 of a turn. But if you're going to do that, why not just go all the way and use tau?

As for the area of a circle, I'd argue that if you are not going to adopt tau as a replacement for pi, you should still express the area of a circle as (1/2)*(2*pi)*r^2, even if you might take a shortcut in actually calculating it. The factor 1/2 can be illustrated as coming from the fact that the calculation of the area of a circle can be seen as a sum of an infinite amount of triangles. The fact that pi involves the factor 1/2 alongside with tau just happens to hide that fact of mathematics by coincidentally cancelling out.

Besides, what's wrong with teaching that the area of a circle is tau*r^2/2? It meshes so much better with lots of stuff, like kinematics for example, but there are many other fields with quantities that behave the same way.

If you have an object accelerating from a standstill at the time t=0 accellerating at a constant acceleration of a, your speed at any given time will be a*t. The distance travelled will be a*t^2/2 - or the area underneath the velocity curve from t=0 to the current time.

At the same time, it meshes nicely with the fact that a circle's circumference is tau*r, and its area is tau*r^2/2.

Re:They've got a point

[Anonymous Coward]

Yes, that's the tau's people response, and it is terrible.

Consider, for instance:

e^(i*0) - 1 = 0

Tau reduces a really curious property/behavior to an apparent triviality. Of course, the reason e^i*tau is 1 is very different from the reason e^0 is 1, but it's not so immediately obvious that something weird is going on as it is when e^i*pi = -1.

Re:They've got a point

[WNight]

e^(i*tau)+0=1

There, art and useful.

Re:They've got a point

[adisakp]

Hmmm... surprisingly well argued points... it's an unusual day for Slashdot. I guess the main reason to use pi instead of tau then is for "backwards compatibility" and "legacy math".

Tau is used everywhere. I prefer k_k

[BetterSense]

Tau is already super overloaded. In grad school, we always wrote "2pi" as k_k, that is, k with a subscript k (it doesn't look as weird in handwriting, because the subscript).

Of course, it's pronounced "cake".

Re:Tau is used everywhere. I prefer k_k

[agentgonzo]

Why on earth did you do this? I've never heard of this notation.

Re:Tau is used everywhere. I prefer k_k

[lattyware]

And of course 3pi was k_k_k... wait...

Re:Tau is used everywhere. I prefer k_k

[BetterSense]

You have never heard of this notation because we invented it. We wanted/needed a better way to express 2pi because, as TFA states, pi is a stupid choice for a constant and when you are doing physics you end up writing 2pi constantly; having a constant for 2pi leads to more intuitive notation that helps to clarify relationships that are less obvious when you have stray factors of two which by rights ought to belong to their pi instead getting loose and wandering about your analysis.

There seems to be some momentum behind using Tau but guess what, Tau is used 3 billion other places in physics so it's a poor choice for a constant that should have a fairly unique name.

All in all, though, the pi thing isn't as bad as people make it out to be. Eventually you just start considering 2pi to be a quantity all its own. If you really want to get riled up over something, I suggest the fact that electrons are negative

Re:Tau is used everywhere. I prefer k_k

[Duradin]

Also, 2pi takes 3 characters, tau takes 3 characters, while .5tau takes 5, 1/2tau and 0.5tau take 6, (1/2)tau 8.

Re:Tau is used everywhere. I prefer k_k

[Anonymous Coward]

Why on earth did you do this? I've never heard of this notation.

You must have missed the last line of the gp post:

Of course, it's pronounced "cake".

Re:Tau is used everywhere. I prefer k_k

[blueg3]

If you're writing out "2pi" and "(1/2)tau", you're doing it wrong.

2 pi either takes two characters, one of which is Greek, or four: 2 \pi.

Re:Tau is used everywhere. I prefer k_k

[Duradin]

"2 \pi"

Funny, I count 5 there.

Re:Tau is used everywhere. I prefer k_k

[blueg3]

Right. I meant to say five. It's offensive LaTeX notation to fail to separate the 2 and the \pi with a space.

Re:Tau is used everywhere. I prefer k_k

[Anonymous Coward]

There are more things in heaven and earth, Horatio, Than are dreamt of in your philosophy.

Re:Tau is used everywhere. I prefer k_k

[Anonymous Coward]

This comes from the old dilemma:
The math teacher, while showing the proof of a theorem: "Suppose we have a set of _m_ elements... Mmm.. No, no, no, _m_ is not enough. Suppose we have a set of _k_ elements..."

Re:Tau is used everywhere. I prefer k_k

[Astazi]

It comes from the ages old dilemma: The math professor, while showing the proof of a theorem: "Suppose we have a set of m elements. Mm... No, no, no, m is not big enough. Suppose we have a set of k elements..."

Obligatory

[Anonymous Coward]

http://www.youtube.com/watch?feature=player_embedded&v=jG7vhMMXagQ#at=290

We already missed Pi Day

[euroq]

I was thinking we already had a Tau Day article on Slashdot, but searched revealed that 3/14 was Pi day: http://science.slashdot.org/story/11/03/14/1329210/Happy-Pi-Day

Pronounciation fail

[Anonymous Coward]

In modern greek, the letter "" is pronounced "taf".

Re:Pronounciation fail

[koreaman]

Who cares? How is this in any way relevant to the discussion?

Re:Pronounciation fail

[Tetsujin]

In modern greek, the letter "insert letter here" is pronounced "taf".

And in Latin, "Jehovah" begins with an "I"...

Date formats on the rest of the planet

[Livius]

Wait, it's not the 62nd of August yet... ...you insensitive clod!

Obligatory Southpark...

[erroneus]

"... Yer a Tau!"

I prefer Pi

[Anonymous Coward]

3.141592 vs 6.283184. And odd numbers are clearly superior to even numbers :).

Besides, Pi is now so deeply ingrained in my brain, I'm afraid there is no hope of updating my brain to the Tau version.

Re:I prefer Pi

[koreaman]

The odd and even numbers are subsets of the integers... neither pi nor tau is odd or even.

Re:I prefer Pi

[Anonymous Coward]

You missed the point.

The first three digits of Tau are even. The first two digits of Pi are odd.
My brain strongly prefers odd numbers to even numbers (even numbers are ugly!), probably related to my brain liking primes over non-primes.
And so for me, my brain has a strong preference for the digits of Pi.

Re:I prefer Pi

[Kompressor]

That's irrational.

Happy tau day to you too!

[Lord Lode]

:)

As a mathematician...

[Anonymous Coward]

I like the idea of tau, especially as a teaching tool. The intuition for dividing up a circle is much better. The arguments over superfluous 2's in numerators or denominators seems, frankly, stupid to me--there's some constant floating around, what it is isn't really crucial to understanding the idea. However, I think it's pretty pointless for me to bring up tau in a college lecture as students have already been indoctrinated to think in terms of pi. I'm not optimistic anything will ever change at the high school level, so it's all academic really (no pun intended).

Tau is already used

[Low Ranked Craig]

Tau is already used to describe the relationship of speed to the apparent speed of the passage of time. Also, both Pi and "Tau" are irrational, and since Tau is 2pi, this seems like a huge fucking waste of nerd time.

Re:Tau is already used

[heathen_01]

The point of Tau is not to please nerds or mathematicians.

Although I would love to see mathematicians change their ways, I’m not particularly worried about them; they can take care of themselves. It is the neophytes I am most worried about, for they take the brunt of the damage

Re:Tau is already used

[koreaman]

Pi is used for things other than the circle constant, too...

Re:Tau is already used

[geekoid]

See, this is what I get for not taking my own advise and using a tilde.

And if he didn't know that, then he should get back to the books and stop wasting time~

now it's funny.

Re:Tau is already used

[blueg3]

All of the Greek and Latin characters are used for more than one thing just in physics alone -- to say nothing of subscripts, typographical variants like blackletter, decorator symbols, and the occasional Hebrew letter.

Re:Tau is already used

[Anonymous Coward]

Who needs another constant to keep track of? I don't see how multiplying by 2 is such a burden. Might as well make a constant for every other common multiple we run into.

Re:Tau is already used

[carpenoctem63141]

Ah, which is why we should adopt Chinese characters. There's no way we'd ever run out of those.

Re:Tau is already used

[Anonymous Coward]

He did know, its in section 4.2 Conflict and resistance. Why don't you read the reasoning, it does make sense.

Re:Tau is already used

[Anonymous Coward]

Why does singing it make it funny?

Re:Tau is already used

[mgiuca]

I know I'm a few days late, but TFA explicitly has an entire section to address this:

Fortunately, although the letter appears in some current contexts, there are surprisingly few common uses. ... Despite these arguments, potential usage conflicts are the greatest source of resistance to . ... But scientists and engineers have a high tolerance for notational ambiguity, and claims that -the-circle-constant can’t coexist with other uses ignores considerable evidence to the contrary. For example, in a single chapter (Chapter 9) in a single book (An Introduction to Quantum Field Theory by Peskin and Schroeder), I found two examples of severe conflicts that, because of context, are scarcely noticeable to the trained eye.

More examples are given, but the point is that many mathematical symbols, including , are already overloaded, and we get along fine.

Re:Tau is already used

[mgiuca]

And I'm not sure what's up with /.'s unicode support. But I don't seem to be able to use the symbols for "pi" or "tau".

For the moment, not persuaded.

[DdJ]

I might agree that it makes sense to switch from pi to tau after I agree it makes sense to change from imperial measurement to the metric system.

Note that at this time I do not agree that it makes sense to switch to metric, so we may be in for a bit of a wait...

Re:For the moment, not persuaded.

[Anonymous Coward]

I don't know if you were asleep, but the imperial vs metric thing is over. The US doesn't have the budget to run a parallel system of units. So it doesn't have one. How far is a foot? No way to know without knowing what fraction of a metre one foot has been defined as by statute. How much energy exactly is a BTU? Trick question, a BTU isn't a standard unit of energy at all, it could be almost any amount of joules of energy depending on how it was measured. The "imperial" units are a joke, either undefined or defined only in terms of metric units and often in counter-intuitive or plain nonsensical ways.

The result is that in surveys we find Americans have no idea what they're buying, they're reduced to estimating by eye as if they lived in the 18th century or systems of weights and measures never even existed. That's the triumph of this "imperial system" that's neither a product of empire nor much of a system.

Re:For the moment, not persuaded.

[LordNacho]

Luckily, you can easily write T=2Pi in your equations. No need to reprint thousands of T-Shirts.

I think the main point of the rant is that Tau somehow seems more fundamental. What defines a circle? A locus of points on a plane equidistant from a certain point. That distance is somehow more fundamental than 2r, even if the distinction is trivial.

Re:For the moment, not persuaded.

[geekoid]

What possible reason could you have not to finish switching to metric?

Re:For the moment, not persuaded.

[Duradin]

Because outside of the world of digital calculators metric sucks?

We can have a quarter pounder with cheese. You have the Royale with cheese. One tells you how much you are actually getting. Otherwise you've got to rattle off "I want a 113.398093g with cheese".

Re:For the moment, not persuaded.

[geekoid]

So labels confuse you?

By your reasons the 'Big Mac' doesn't make sense and no one could possible know how much meat is there. In fact, how many burgers are known by there weight? A very few, overall.

It is far easier to teach kids metric then imperial. They get it faster, it makes sense. Kids like there to be a graspable reason for doing things. Metric has that.

It's also become incredible more expensive and difficult to work outside the US without using metric.
That said, if the US official went metric, that would not mean private corporations would have to change what they call food. In England you still order a pint of beer.

Re:For the moment, not persuaded.

[Dr_Barnowl]

But I'm sure Americans are gonna love the Quarter-Kilo with Cheese. More than double the beef of the Quarter Pounder!

Re:For the moment, not persuaded.

[Duradin]

Aren't England's road signs in miles as well (and weight still given as stones by the populace)? Great example of metric adoption there.

Re:For the moment, not persuaded.

[treeves]

No, McDonalds would have to go to the 1 Hectogram with Cheese for economic reasons (and it'd make dietary sense too), and they'll lose just a little meat. "Hectogram" just sounds so scientific and mathematical and not so tasty.

Re:For the moment, not persuaded.

[geekoid]

I have no idea, I have never been there, I just happen to know they order in pints.

While I may not have travel the worlds, I know how the world drinks beer. Also, I can ask for 2 beers in 8 different languages.

My point still stands.

Re:For the moment, not persuaded.

[Anonymous Coward]

I have to wonder if the metric-wary really believe that metric countries all start from imperial units and work their way back to metric, keeping 3+ places after the decimal point. This comment (or joke?) shows up surprisingly often.

Your gas pumps show gallons with the fractional part in hundredths or thousandths, and it isn't like you don't know how much gas you're getting. "6.578 gallons!? WTF does that mean! Oh, 6 and 37/64 gallons. Phew, now I'm on solid ground."

Re:For the moment, not persuaded.

[hendrikboom]

The meat in a quarter-pounder doesn't even weigh a quarter-pound. It did before it was cooked, but in cooking, the weight goes down.

Re:For the moment, not persuaded.

[camperdave]

You already ARE metric. It's just that you're using odd units. Feet, yards, pounds, gallons, every unit you want to hang on to is defined from metric units, and has been since before you were born. Ditch your ounce-of-gold-is-heavier-than-an-ounce-of-lead,-but-a-pound-of-gold-is-lighter-than-a-pound-of-lead ways and your multiple definitions of a mile, and your arcane unit-to-unit conversions and join the rest of the world in decimalized bliss.

Re:For the moment, not persuaded.

[Frank T. Lofaro Jr.]

1 btu = 1 055.05585 joules

according to Google, you metric bigot!

it is NOT unstandardized.

Re:For the moment, not persuaded.

[Actually, I do RTFA]

What possible reason could you have not to finish switching to metric?

Manly American Football is played on a 100 yard field. Sissy Canadian Football is played on a 100 meter field. I refuse to see our beloved sports (e.g. Baseball is defined in yards as well) redefined, therefor causing old records to be irrelevant.

More realistically, I have no idea why base 10 is a great idea. Imperial has binary units (volume/mass) and base twelve units (hello 1/3!). Either standard seems better than base 10.

Now, if you said we need to make imperial conversions more uniform, I whole-heartedly agree. But I'd rather start doing all mathes in base 12 or 2 or 16 then switch units to base 10.

Re:For the moment, not persuaded.

[Tetsujin]

1 btu = 1 055.05585 joules

according to Google, you metric bigot!

it is NOT unstandardized.

How many litres in a gallon?

Re:For the moment, not persuaded.

[Tetsujin]

Luckily, you can easily write T=2Pi in your equations. No need to reprint thousands of T-Shirts.

I think the main point of the rant is that Tau somehow seems more fundamental. What defines a circle? A locus of points on a plane equidistant from a certain point. That distance is somehow more fundamental than 2r, even if the distinction is trivial.

It's not about the ratio of the circumference to the radius (or diameter) - it's about the fact that all this other math that uses pi winds up needing an extra factor of two... When you're working with arc lengths or integrating circumferences, you're generally working with radius and multiplying by 2*pi.

I'd agree from a practical standpoint it's fairly silly to think of switching people to using tau (equal to 2*pi) in their calculations instead of pi. But it's worth thinking critically about those kinds of decisions, the slightly arbitrary choice of which version of the constant we use, if there may be clear benefits to an alternative choice. And regardless of whether any kind of actual switch takes place, it's worthwhile to at least recognize the idea that 2*pi may actually be a more important constant than pi. Exploring ideas like that holds the potential to usefully change how you think about math.

Re:For the moment, not persuaded.

[Tetsujin]

Because outside of the world of digital calculators metric sucks?

We can have a quarter pounder with cheese. You have the Royale with cheese. One tells you how much you are actually getting.

That's pre-cooked weight, so no it doesn't.

The Emperor is my Shield!!!!!

[belligerent0001]

Aren't Space Marines, perhaps even the Imperial Guard the best war to deal with the Tau?

Illustration

[Anonymous Coward]

Pi is wrong, cute video
http://www.youtube.com/watch?v=jG7vhMMXagQ

IT'S ALSO WORLD CAPSLOCK DAY

[CmdrPorno]

(Which apparently triggers the lameness filter...)

IN MEMORY OF BILLY MAYS! DON'T JUST CLEAN IT, SCREAM AT IT!

Why does the lameness filter think Billy Mays is lame?

Re:IT'S ALSO WORLD CAPSLOCK DAY

[Anonymous Coward]

Well, he is dead, so by that reckoning he is quite lame too.

Re:IT'S ALSO WORLD CAPSLOCK DAY

[geekoid]

Because Billy Mays is lame.

He's a guy the screamed at us to buy crap.
For a site that has a lot of people who hate advertising, why is Billy Mays so popular?

Re:IT'S ALSO WORLD CAPSLOCK DAY

[Trilkin]

Personality.

Re:IT'S ALSO WORLD CAPSLOCK DAY

[tepples]

why is Billy Mays so popular

Go on YouTube and search for suicide jack, suicide putty, or suicide hooks.

Re:IT'S ALSO WORLD CAPSLOCK DAY

[geekoid]

So screaming at people to by shit is not a personality plus?

To me his was the pinnacle with all that is bad about advertising.

Re:IT'S ALSO WORLD CAPSLOCK DAY

[Martin Blank]

According to numerous sources, he never advertised anything that he didn't personally believe in and use, at least since he founded his company. A journalist who interviewed him at his home reported seeing many of the products that he sold around the house and in apparently regular use. He rejected many more items than he accepted. Advertising may be a slimy industry and he may have been hard to avoid, but he did seem to have a spine.

Re:IT'S ALSO WORLD CAPSLOCK DAY

[simmonsjeffreya]

Don't forget Suicide Ladder, possibly the best one, minus the Halo crap at the end.

"Your entire family wishes you were dead, even your dog."

We physicists and EEs also need...

[darenw]

exp(2 pi i x) where x is some simple expression of time or distance occurs a *lot*. Years ago, I invented a symbol for exp(2pi*i): a one with a tilde superimposed in the middle. e^(2pi*i) does indeed compute to 1.0, but taken to some power x, of course we don't mean (1)^x but what exp(2 pi i x) normally means. A one with a tilde superimposed reminds us to do this. This notation makes many formulas involving Fourier transforms, waves, AC circuit analysis, and quantum mechanics nice and elegant, and 1 with the tilde is not a challenge for Latex or Lout.

For 2pi, I sometimes use a circle with a dot at the center. Tau is way too overloaded, as has been pointed out already.

Re:We physicists and EEs also need...

[Frank T. Lofaro Jr.]

It's 2011, no one uses LaTeX anymore.

People use latex, but that is a different thing.

^^This

[Slutticus]

Just seems natural. or something. zen maybe.

Tau is already used

[geekoid]

And if he didn't know that, then he should get back to the books and stop wasting time.

Yin and yang

[tepples]

Look at the taijitu, a common symbol of yin and yáng in Taoism. Yin occupies pi radians of the symbol, as does its opposite yáng. The whole symbol, all tau radians of it, represents a whole made up of a balance of parts that are opposite. You need all tau radians to represent the balance of nature maintained by the active force called the Tao.

Re:Yin and yang

[mr_mischief]

So the tau that can be named is not the true tau?

Re:Yin and yang

[geminidomino]

I hate you for that. Just thought you should know.

Coffee in the sinuses hurts, you bastard.

Re:Yin and yang

[Mindcontrolled]

That is a natural consequence of the fact that the numbers you can count are not the real numbers.

Re:Yin and yang

[Anonymous Coward]

The name is merely the beginning, the source.

But pie are square

[Anonymous Coward]

area = pi*r^2 is nice and simple - pie are square

area = (tau*r^2)/4 just doesn't roll off the tongue - quarter tau are square

Re:But pie are square

[Anonymous Coward]

area = pi*r^2
pi = tau / 2

This means:

area = (tau/2)*r^2 = (tau*r^2)/2

Don't know where you got your 4 from.

This meshes perfectly well with other expressions on the form a*b^2 / 2 which have to do with areas. Like m*v^2/2 or a*t^2/2.

Tau and pi: tally marks in the denominator

[tepples]

Why call it tau? Couldn't you call it, say, two-pi

The symbol for tau is a line over one vertical mark (/ I). The symbol for pi is a line over two vertical marks (/ II). You could consider this to represent a fraction bar with a Roman numeral in the denominator, and thus tau and pi represent different denominators: tau is the circle constant divided by 1, and pi is the circle constant divided by 2.

Sophomoric number humor

[Anonymous Coward]

Hair Pi vs Camel Tau... tough choice

Tau ... zero?

[AliasMarlowe]

Everybody knows that tau is actually a variable which depends on velocity of one observer relative to another. Poul Anderson even wrote a nice SciFi book called Tau Zero.

by Livius (318358) on 2011-06-28 11:16

[tepples]

The international standard on the planet where I live is ISO 8601, which calls today 2011-06-28.

Why not both?

[RyuuzakiTetsuya]

Tau for uber math nerds, physicists, EE geeks and anyone else who needs to calculate an arc tangent and Pi for everyone who just needs to figure out what diameter pipe they need to fix their sink?

Re:Why not both?

[Nethemas the Great]

You mean kinda how we screw up elementary and middle school students with a different set of symbols for the multiplication and division operators? Sure why not, lets add more stumbling blocks.

Re:Why not both?

[Anonymous Coward]

Why would physicists and EEs use tau for a circle constant when tau already has meaning in the situations where pi would be used? They like ambiguity of notation and possible confusion? If anything, this tau nonsense is being pushed by people who don't actually use math.

Re:Why not both?

[jpmorgan]

Pi is better for uber math nerds, physicists and EE geeks because there are lots of circumstances where you deal with the integer multiples of Pi, including odd multiples. The only people who like 'tau' are the math/science groupies online who worship, not practice, and think that Fermat's Last Theorem was an important problem.

Re:Why not both?

[Anonymous Coward]

As an EE, I say fuck tau. One, tau is used for time constants. Two, a larger circle constant means more fractional coefficients to deal with. Fuck that.

Re:Why not both?

[the phantom]

I think you have it backwards. Tau is somewhat easier to work with, and is (arguably) more intuitive. Beginning students are likely to understand tau better than pi. These would be the kinds of people that might want to figure out the diameter of a pipe or whatever. Mathematicians, physicists, and so on will do okay with any notation, be it pi, tau, or the three-legged symbol that Palais suggests.

As is pi

[tepples]

Tau is already used to describe the relationship of speed to the apparent speed of the passage of time.

And pi is already used to describe conjugate momentum, as Tau Manifesto explains. Wikipedia lists a whole bunch of other meanings of pi.

Writing as quickly as thinking?

[tepples]

But the real lesson is showing the work so when it's not that easy you can get a correct answer.

So it has become a problem of input devices. I think divide by 4 on each side, but how do I write this down as quickly as I think it?

Sorry,

[Anonymous Coward]

but I cannot respect any man in a vest.

Regarding the music

[BrokenBeta]

I listened to the tau music, then went back to listen to the pi music, then listened to the tau music again.

It's odd, the tau music is clearly "better" in a musical kind of way, but it's the pi music which is rigidly stuck in my head.

Beautiful

[2names]

That is quite possibly the most beautiful song I've ever heard.

Re:Beautiful

[Twinbee]

I hope you're joking. The instruments make it sound better than it really is.

You do realize you'd get similar crap with random numbers.

Re:Beautiful

[2names]

You're not seriously trying to apply objective reasoning to an opinion, are you?

Re:Beautiful

[Twinbee]

Many things are hard to assess and could even be considered subjective, such as programming or CPU speed benchmarks. Doesn't mean there isn't a measure of 'goodness' or 'efficiency' that can be applied.

Music granted is more tricky (at least with our current level of knowledge) to determine a rating. But if they had picked a truly random number, and made music from that, they could have made that sound 'good' as well (especially since the simple diatonic scale is used). And I wonder if you would have had the same reaction then.

How about Tao day?

[davidwr]

Everyone chant...

Ohm

Ohm

Ohm

Resistance is futile.

Re:How about Tao day?

[ginbot462]

>> Resistance is futile.

Resistance may be futile, but we keep doing it. In the naive hope, that one day ... it will be our leap home.

This will not end well? Too many pies?

[Anonymous Coward]

Let's see. One side has pies, the other side has twice as many pies. Can you say "arms race"?

I can't decide whether this fight is going to be delicious or if it is going to turn every mathematics conference and June 28th/March 14th into a Cold-War-style pietastrophe.

2*Pi Day?

[Jason Levine]

Celebrate a day based on 2*pi? No thanks. However, I will celebrate 2.556*pi day. I will likely even have cake on that day. It's the day that I turn approximately 11.46*pi years old.

Pi is already used

[Anonymous Coward]

And if you didn't know that, then you should get back to the books and stop wasting time.

Seriously, know your stuff before you start blasting others for re-using symbols.

In fact, using this as an excuse is downright retarded at best.
You do not deserve the name geekoid. You ain't no geek to me. Hand that card and name in.
Also, that language you are using, you should stop using it, it is silly, it re-uses words to mean countless different things depending on the context.

Actually...

[Joepat]

Pfft. Forget Tau Day. Today's my birthday. =D

For the Greater Good!

[Chris Mattern]

It is the only way.

Context!

[guspasho]

Twice as many what as you'd expect? Pies that are being served at the end? Don't make me read the article to understand the summary.

What?

[Anonymous Coward]

The only explicit multiplication operator is the dot (slightly higher than the decimal point), for division a slash can be used if there is no space for a normal horizontal line between divisor and divident.

Are those not used in elementary and middle school in the US?

Re:What?

[Anonymous Coward]

When I was in primary school, division was done using an operator similar to the square root operator but with something like a right parentheses on the left hand side instead of a broken V.

The number to divide went on the inside while the number to divide by went on the left of the operator. And the result went above the operator.

As far as I'm aware it was done this way so as to provide space below the operator for long division. We barely ever did any of that, though.

6/28 already has mathematical significance

[treeves]

It's Perfect Number day, as 6 and 28 are both perfect numbers.

Proper divisors of 6: 1, 2, 3
1+2+3 = 6

Proper divisors of 28: 1, 2, 4, 7, 14
1+2+4+7+14=28

The next perfect number is 496, so all of the perfect numbers that can be dates are 6 and 28.

It's those pesky humans

[sootman]

Yes, math works better with relation to radius than diameter, but for a human, walking up to an already-drawn circle, you can either a) measure the diameter (100% effective and accurate) or b) estimate where the center is and measure to it (and get a result that is only as good as your estimation--half as good, actually, since doubling the number would double the error.) Thus "diameter" took off as "the main way we humans measure circles." Yes, you can very easily half the diameter, but what's the point if you're going to multiply by a constant to find the circumference? If you want to find out how much rope you need to tie around a well, would you 1) measure the diameter, 2) divide that number by 2, and then 3) multiply by tau, or would you 1) measure the diameter and 2) multiply by pi?

Same thing with Imperial vs. Metric measurements: yes, Metric makes the math easier, and we do indeed have ten fingers, but if you have something you want to divide, it's a lot easier to cut it in half, and half again, and half again, and anyone can do so easily--even on irregularly-shaped things like "a pile of cooking flour"--as opposed to trying to cut something into ten equally-sized pieces.

I'm not saying any of the above are absolutely better or worse than the others, but humans have certain natural tendencies, and that's where this stuff comes from, and why it's hard to change.

Re:It's those pesky humans

[PagosaSam]

but for a human, walking up to an already-drawn circle, you can either a) measure the diameter (100% effective and accurate)

Sorry, if you "walk up on a circle" you can't guess at a diameter either. You have to make a geometric construct to find the center so your diameter measurement is correct. You might as well measure the radius at that point.

Re:It's those pesky humans

[sootman]

I said measure the diameter, not guess the diameter. The only "guessing" I mentioned is the requirement of guessing where the center is if you want to measure the radius.

Here are a couple examples of what I had in mind when I said that measuring a diameter is easy:
- you see a circle painted on the wall. Pull out a ruler or a tape measure. Done.
- you come across a poured concrete circular fire pit on the ground. You and a friend stand on opposite sides of it and stretch across a tape measure. Done.

> You have to make a geometric construct to find the
> center so your diameter measurement is correct.
> You might as well measure the radius at that point.

LOL. You've got it exactly backwards. Measuring diameter is easy. You stretch a measuring device across a circle from one side to another. You hold the "zero" end in place and wiggle the other end a bit until the observed measurement is as large as possible--i.e., the widest part; a.k.a. "the diameter." No guesswork is involved and the precision is very high. Compare that to having your friend hold the end of the tape measure in what he thinks is the exact center of the circle...

Sure, you can accurately find a circle's center point. How do you do that? By drawing two intersecting diameters! "Two diameters" IS the "geometric construct" you use to find a circle's center point. (Sure, you could also do two chords, each with a perpendicular line at the midpoint, but outside of a geometry class, playing with a compass and straightedge, how likely are you to do that? And again--how many steps is that?) Saying "Using two diameters to find the center to find the radius is easier than finding one diameter" is literally nonsense. Give me an unmarked circle to measure and a measuring device long enough to span it (and, if needed, an assistant) and I will find the diameter faster and more accurately than you will find the radius every time.

Bonus: you get a more accurate number by measuring a diameter and cutting it in half than by measuring the radius itself.

Re:It's those pesky humans

[Tetsujin]

I said measure the diameter, not guess the diameter. The only "guessing" I mentioned is the requirement of guessing where the center is if you want to measure the radius.

Here are a couple examples of what I had in mind when I said that measuring a diameter is easy:
- you see a circle painted on the wall. Pull out a ruler or a tape measure. Done.
- you come across a poured concrete circular fire pit on the ground. You and a friend stand on opposite sides of it and stretch across a tape measure. Done.

If the measurement doesn't go through the center of the circle, then you got it wrong.

Re:It's those pesky humans

[sootman]

Seriously? Did you read my whole post? One more time for the cheap seats:

Measuring diameter is easy. You stretch a measuring device across a circle from one side to another. You hold the "zero" end in place and wiggle the other end a bit until the observed measurement is as large as possible--i.e., the widest part; a.k.a. "the diameter." No guesswork is involved and the precision is very high.

If the circle is good, using my patented "measure the widest part of the circle" (c) (R) (TM) method will ensure a measure that goes through the center of the circle.

Confusing and unnatural?

[blair1q]

"Pi is a confusing and unnatural choice for the circle constant."

Unless you're trying to pack amphorae into a cargo hold and calculate your profit on the voyage.

Seriously, there's not much more natural and distinctive than

Korg: "How big is a circle"?

Ugg: "You mean how big across or how big around?"

Korg: "OoooOOOoohhhh, look who's been going to college!"

Wrong value for tau

[hendrikboom]

Eagle, in his book "The Elliptic Functions as they Should Be" has already introduced tau as one-half pi, saying it's natural to use a one-legged letter as half of a two-legged letter.

Physics vs. mathematics

[JazzHarper]

In effect, engineers and physicists eliminated the constant '2' a long time ago by adopting the symbol omega, which is equal to 2pi*f, not pi*f, for angular frequency. That leads to the definition of complex frequency, s, which is used in most applications of Laplace and Fourier transforms.

Mathematicians and teachers of trigonometry are more likely to cling to the symbol pi.

Octaves...

[regular_guy]

I don't enjoy how he identifies 9 notes for a scale (or identifies it as a rule.) 9 chords to identify the numbers and leaving 0 as a rest, it's an ok interpretation, but I hope there's something better out there. The whole thing sounds and looks like a "made on a Mac" hipster nonsense.

So what about the Gamma Function?

[Anonymous Coward]

This does not account for the Gamma Function. Using tau would make solving integrals actually ugly.
Maybe it is smart for angles, but that is about it.

PI not TAU in Euler's identity

[peter303]

Euler's Identity assembles the five basic constants of math into a compact equation: e, pi, i, 1 and 0. No two or tau in there. This is sometimes called 'The most beautiful equation in mathematics'.

Re:PI not TAU in Euler's identity

[Peter Mork]

Time to read the article: e^(i \times \tau) = 1 + 0. The reason that e^(i \times \tau / 2) = -1 is because \tau / 2 = \pi corresponds to a half-rotation. So, you can get the same result, only with a more intuitive answer because the amount of rotation is built into the equation. This helps to understand that e^(i \times \tau / 4) = i because i corresponds to a quarter rotation.

Re:PI not TAU in Euler's identity

[Anonymous Coward]

e^(i*tau) - 1 = 0

Or just:

e^(i*tau) = 1

Which is a lot more beautiful and symmetric than the comparatively clunky:

e^(i*pi) = -1

The number of constants involved in a formula doesn't neccessarilly make it more beautiful. After all:

e^(0*i*pi*phi*tau*lulzsec*31337) = 1

Re:PI not TAU in Euler's identity

[impaledsunset]

The beauty of the Euler equation with pi is that you get an unexpected result if you haven't dealt with complex exponents before. It is not only beautiful, but it also shows that your expectations that the power of a positive number must be a non-negative number is *wrong*. You gain insight into complex exponents. The same equation with tau is simply a fancy way to write e^0, because tau*i is the period of the exponential function. True, a periodic exponential function is slightly surprising to someone who is just studying this, but it is still just "ah, ok, the imaginary part up there just makes it oscillate like a sine, cool", not "WAT?"

Equal Time For "e" Day!

[0xG]

(e = 2.71828183) ...that would be: February 72...
Never mind.

Prosper, as Tau shall

[Anonymous Coward]

We serve the Greater Good.

Damn you, I'm a Mech Engineer, not a Mathemetician

[Gadgetfreak]

We already use Tau for both torque and for shear area. The nature of both types of calculations typically involves circles, and therefore, pi. Yeah, I'm nitpicking, but the last thing I need is for my simple calculations to have three different uses of the same damned Greek letter.

Everyone knows pi. It's too late, it's been the standard for generations. The same goes for the English language - it sucks, but even though it makes logical sense to change to something better, good luck trying to get everyone on board that train.

M_TAU

[NoOneInParticular]

To honor tau we should update math.c with M_TAU referring to M_PI_2. BTW, what would occur more often, M_PI, or M_PI_2 in actual code? And how often do people use 2 * M_PI?

what about the derivative?

[Anonymous Coward]

This is a very stupid idea for one important and untouched on (the site barely touches on it but does not address the problem) d (sin x)/dx=cos x only in radians, therefore using tau instead of pi would create troubles for the derivative and make it unnecessarily complicated.

Re:what about the derivative?

[Anonymous Coward]

Um... no. It is not a stupid idea. It is you who are being stupid. :-P

Using tau = 2*pi does not in any way break integration, because we're not changing the units involved, only the conventional way it is being expressed.

Expressing the angle 60 (one sixth of a turn) in radians can be done equally well no matter if you express it as tau/6 or pi/3. They're both approximately 1.05 radians either way. It's just that it's more natural to think of 60 as "one sixth of a whole circle" rather than "one third of a semicircle".

And since we are not changing the units involved - it's still radians - integration and derivation will work just as well as before, thank you very much.

If it bothers you, just pretend that wherever you see tau, it actually says 2*pi. And then you will see that everything is exactly equivalent. :-)

lim sin(x)/x = 1, when x->0

[saigon_from_europe]

But if we redefine radian, lim sin(x)/x = 2

Pie are square?

[sgt scrub]

Pie are round. Cake are square. Anyone edjumicated in Texas knows that. Long live the Tau!

Re:lim sin(x)/x = 1, when x-0

[Anonymous Coward]

Why would we redefine radians? The whole point of radians is to have the angle correspond to the arc length on a unit circle. This also allows us to avoid constants when differentiating/integrating sin or cos, in other words to have lim sin(a+x)/x = cos(a) when x->0 and lim cos(a+x)/x = -sin(a) when x->0.

I only like Tau

[Anonymous Coward]

when it pertains to food - i like two pies more than one...
for all other purposes i don't give a damn.

You made me remember this little jewel...

[elsurexiste]

Hardware met Software on the road to Changtse. Software said: “You are Yin and I am Yang. If we travel together we will become famous and earn vast sums of money.” And so the set forth together, thinking to conquer the world.

Presently they met Firmware, who was dressed in tattered rags and hobbled along propped on a thorny stick. Firmware said to them: “The Tao lies beyond Yin and Yang. It is silent and still as a pool of water. It does not seek fame, therefore nobody knows its presence. It does not seek fortune, for it is complete within itself. It exists beyond space and time.”

Software and Hardware, ashamed, returned to their homes.

Section 8.4. The Tao of Programming.

So, they thought they'd have a piece of Pi ...

[donak]

And ended up with twice as much ?

Metric metres.

[Tetsujin]

What possible reason could you have not to finish switching to metric?

Manly American Football is played on a 100 yard field. Sissy Canadian Football is played on a 100 meter field. I refuse to see our beloved sports (e.g. Baseball is defined in yards as well) redefined, therefor causing old records to be irrelevant.

More realistically, I have no idea why base 10 is a great idea. Imperial has binary units (volume/mass) and base twelve units (hello 1/3!). Either standard seems better than base 10.

It's a fair point, but the main issue to my mind is that they didn't pick a base and stick with it, rather the conversion factors are all over the map. Teaspoons-to-tablespoons is a factor of three, but up to cups, pints, quarts, and (US) gallons is a power of two. Inches to feet is factors of twos and three, feet to miles is factors of two, five, and eleven. And fractions of inches are powers of two, unless you're dealing with mils in which case it's powers of ten. And there's no straightforward conversion between the length and volume measures, or (as you get into physics calculations) the length, weight, and force. One cubic foot is 7.48051948 US gallons.

Had the system been planned better, I think the disparate conversion factors could be quite acceptable: 12 inches per foot is reasonable, potentially helpful in cases that involve division by a factor of three. Working with arc-degrees and the fractions thereof (arc-minutes, arc-seconds) is similarly reasonable. The bigger problem is that some of the conversion factors aren't even integers.

Speaking personally - I build models and deal with small measurements a lot. In that context I'd rather deal with powers of ten rather than powers of two. I can do fractional math, obviously, but it's still easier to work out the drill bit sizes between 3mm and 5mm than it is to work out the drill bit sizes between 1/8" and 13/64" - even if I change the denominator (i.e. 3.5mm has an extra digit, so I'm effectively working in ten-thousandths of a meter instead of thousandths) the change to the numerator is trivial. Power-of-two changes to the numerator are pretty easy but not as easy, simply because my numerical representation isn't powers-of-two.

There is a flip side to that scale modeling scenario, which is that kit scales are in many cases chosen specifically to suit the foot-to-inch conversion factor. For instance, a six-foot-tall man would be exactly one inch tall in 1/72, or three inches tall in 1/24. That is handy, but it becomes less helpful if the measurement you're converting isn't that fundamental measurement on which the scale was based. The scales have factors of three - if you're starting with feet, one of those gets eaten by the inch conversion... But if you're starting with a measurement in inches and going for a fractional measure of inches, the factors of three have to be used to divide the numerator... eleven inches scales down to (11/9)/8 in 1/72 scale, for instance. Converting that to the closest power-of-two fraction means finding the right denominator... (22/9)/16 or (44/9)/32 or (88/9)/64 - scaling up the numerator enough to find a good answer, and then scaling it back down to a satisfactory precision. (44/9 is slightly less than 45/9=5, so 5/32 would be a good approximation..)

Dealing with a problem like that in metric is actually easier IMO, even though the unit conversions don't eat any of the scaling factors. 28cm / 72 = 3.5cm / 9, very close to 3.9mm. (Well, the 28cm measurement comes from a conversion from the 11" measurement I used in the inches example, so it may be a bit too convenient as 28 already carries two factors of two... If it were a prime number, as in the previous example - say, 31cm/72 = 10.33cm/24 = 3.44cm/8 = 4.3mm) It's convenient to not have to change bases at any point during the calculation, even if that means some cases are less convenient.

Of course, with the right calculator you can handle all those

And I thought this referred to...

[Urkki]

And I thought this referred to something else... 2pi? Booooring.

Bah.

[Geminii]

Two pi, don't bother me.

Re:Damn you, I'm a Mech Engineer, not a Mathemetic

[impaledsunset]

Yes, tau is a bad choice, it means far too many things already. But I'm happy to celebrate the curve torsion day. And proper time day. And Tau Ceti day.

Re:lim sin(x)/x = 1, when x-0

[impaledsunset]

This doesn't redefine the radian. It simply changes the way you write it down.