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No, really, pi is wrong: The Tau Manifesto (Tau Day, 2010)

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Re: No, really, pi is wrong: The Tau Manifesto (Tau Day, 2010)

#91

Post by samatman »

amalcon wrote: post #79
Groxx wrote: post #58

Earlier quoted context omitted.

How many symbols aren't in use, though? If you've got a notably better one, the "manifesto" may consider changing, but they seem (to me) to have pretty good reasons for choosing tau.

I'd ideally prefer to pick one that isn't used in angular things. Because non-English, non-Greek glyphs are somewhat underused for this sort of thing, and because of visual similarity to pi, I'd suggest the hebrew Het or Russian л. However, I really have no problem with continuing to use the multi-glyph symbol 2pi.

Too much visual similarity to pi is a recipe for many factor-of-two errors.

Re: No, really, pi is wrong: The Tau Manifesto (Tau Day, 2010)

#92

Post by nudge »

mitjak wrote: post #89
edanm wrote: post #80

I really hope this convention gains wide adoption. It's pretty obvious to me that it just makes mathematics make more sense, at exactly the time when it needs to make more sense (people learning maths in high school). Until then, here's the trick I'm using: whenever I need to use pi, especially when it comes to the unit circle and radians, I'm just going to do it in terms of tau, then convert at the end. I just wish…

>It's pretty obvious to me that it just makes mathematics make more sense, at exactly the time when it needs to make more sense (people learning maths in high school). People have been studying math at schools for quite a few centuries from what I recall. There's never a better time in this case.

"the time when" is used here to mean "the period in a person's life" rather than "the period in history".

Re: No, really, pi is wrong: The Tau Manifesto (Tau Day, 2010)

#93

Post by krschultz »

amalcon wrote: post #81
mhartl wrote: post #73

Earlier quoted context omitted.

I mention torque in the manifesto, but I wasn't specific enough in this case, and I've added an example addressing this issue at http://tauday.com/#sec:four_arguments . The short version is that when necessary you can easily add a subscript to avoid ambiguity, such as tau_R for rotational torque. (Superscripts work, too. Particle physicists deal with pions, which are represented by the letter pi, but all the symbols…

The thing is, torque is a particularly bad thing to conflict with. While you're not using torque every time you work with pi, you usually end up using pi every time you work with torque. edit: It's much like using i for both sqrt(-1) and for current. Electrical engineers need to use both of these all the time, so they often use j for sqrt(-1) instead.

Or you could use M for moment and stop using tau for torque. Most mechanical engineers talk about moments with M instead of tau.

Re: No, really, pi is wrong: The Tau Manifesto (Tau Day, 2010)

#94

Post by techiferous »

ScotterC wrote: post #60
amalcon wrote: post #38

Earlier quoted context omitted.

I have no problem with people trying to do this in principle. I really don't care enough, but other people can. The symbol "tau", however, is an especially poor choice for a trigonometric symbol, because it's also used for torque. You won't get many physics teachers to change over if every time you try to calculate a torque from a force and radius, you run into a symbol conflict.

My first thought exactly. Mechanical engineers and physicists appreciate where Tau is at the moment. But as someone notes, there is always symbol conflicts.

"at the moment"

very funny ;)

Re: No, really, pi is wrong: The Tau Manifesto (Tau Day, 2010)

#95

Post by pyrtsa »

rudd wrote: post #82
dgritsko wrote: post #44

Earlier quoted context omitted.

Did you get all the way down to here? http://tauday.com/#sec:euler_s_formula e^(i*tau) = 1 Much nicer that way.

I actually disagree that that is nicer. e^(i pi) = -1, which means you can square both sides to come to the also factual statement, e^(i tau) = 1. However, if you only knew the latter you'd be wondering whether e^(i*pi) would be 1 or -1.

I actually disagree with that logic as well. If you just knew that e^(i * pi) = -1, then how would you know, whether halving that exponent would yield +i or -i?

Considering that, we'd need to state Euler's identity as: e^(i * pi/2) = i, but again we'd know nothing about fractions of that exponent. And there we go!

The point is, Euler's identity is a nice property of the definition of complex numbers, but in itself, not too generic. That's why OP's form, e^(i*tau) = 1, would do just fine.

Edit: fixed asterisks.

Re: No, really, pi is wrong: The Tau Manifesto (Tau Day, 2010)

#96

Post by pbhjpbhj »

jokermatt999 wrote: post #18

Well, at least this is a lot smarter than the "pi is exactly 3!" movement.

There are two standard rebuttals.

One is that the thickness of the vessels wall (hands-breadth) is not taken into account in the establishment of 3 as the value being used for pi despite this being mentioned right there in the text, this apparently gives a value of 3.1414 for pi.

The other is that 1 Kings 7:23 reference uses a special rendering of the term line (Hebrew numbers are expressed using letters) such that the ratio of line to ordinary line and the rendering in the text give the actual value as:

3 * 111/106

This gives Pi accurate to 0.00026%.

This all seems quite ex-post-facto but Hebrew has a strong tradition of numerology and this "special" variant of the word line is used only 3 times and always referring to circular objects.

---

Example references: (short) http://msmvps.com/blogs/coad/archive/2010/05/14/pi-in-the-bi..., (longer) http://www.bibleprobe.com/pi.htm, (several refs) http://www.math.ubc.ca/~israel/bpi/bpi.html, (with alternate based on "hands-breadth") http://ldolphin.org/pi/index.html though I'm not sure on the original source.

Re: No, really, pi is wrong: The Tau Manifesto (Tau Day, 2010)

#97

Post by ww520 »

camiller wrote: post #11
ww520 wrote: post #7

Is this a parody or for real?

I think real. Although I didn't read all of the article I think the main thrust was that since 2pi appears in so many places in math that a constant based on the ratio of circumference to radius rather than diameter would be more appropriate. Realistically I think there are better ways to spend your time but ....

Is it like converting from Queen's system to metric system in U.S.?

Re: No, really, pi is wrong: The Tau Manifesto (Tau Day, 2010)

#98

Post by techiferous »

whyenot wrote: post #17

I really like this "modest prpoposal." In its spirit, I suggest that from now on we refer to 13 pies as a "taue," sort of a bakers' dozen of pies as it were. Tau Day will be the new Pi day, but students would be inspired to bring and share many times more delicious home baked goods as before.

I love the idea, but I think a better conversion would be 2 pies = 1 taue. :) Twice as much pie on Tau Day! :)

Re: No, really, pi is wrong: The Tau Manifesto (Tau Day, 2010)

#100

Post by graywh »

samatman wrote: post #90
TheBurningOr wrote: post #83

Earlier quoted context omitted.

I would argue though that the torque example is a particularly problematic symbol conflict as any equations involving torque are by definition going to include many, many references to the circle constant. Yes there are other symbol conflicts in math, but usually they are separated by logical fields (you generally are not doing using e when dealing with the charge of an electron constant (except in the case that you…

I would suggest a change to uppercase Gamma, which looks like a T, kinda. Also, it has always struck me as a looking kind of like a moment arm. Something like this is bound to happen if mathematics pedagogy moves to tau as the circle constant, which it should. The math department has no motivation to respect physics convention, and the physics department will just have to get in line, eventually.

Or physicists/engineers will do their own thing, as seen by using j = sqrt(-1).

Also, uppercase gamma is already used, too. http://en.wikipedia.org/wiki/Gamma_function

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