All I have to observe is this - people who spend their time thinking about changing 2π to tau are not spending it doing, you know, ACTUAL mathematics.

Pi vs Tau reminds me of Qwerty vs Dvorak... the small gain in simplicity (or typing speed) is more than offset by the burden of the change, and learning to use both would be more confusing than using the current standard.

I'd be fine with the change, but I think π is cuter. =)

@rottenseed: Well, as a physicist, I definitely encounter the factor 2*pi much more often than pi. I conjecture that this is true in mathematics as a whole as well, since 2*pi = tau is one full turn of a circle, and one full period of a (co)sine wave. Tau is as such a more convenient choice, if you have the luxury to choose.

>> ^Ornthoron:

>> ^rottenseed:
>> ^Ornthoroneriously, read the manifesto. Area = (tau/2) r^2 actually makes more sense, too.

Dude that manifesto is fucking hilarious...all of this math knowledge spouted and all for what? All because he doesn't like doing fractions??? Really??? Yea let's rewrite all the math texts since before Princia Mathematica just so you can use tau/6 instead of pi/12. That's useless knowledge wasted on somebody with no common sense. Furthermore, it adds unnecessary fractions in things like Euler's identity and like what you just pointed out, the area of a circle.

Well, it's certainly unrealistic to expect that we can get rid of pi in favour of tau after over two millenia of pi's monopoly. But one can dream, can't one?


What I'm saying is that there's no reason to get rid of it...why's it worth trading 2*pi here for tau/2 over there?

>> ^rottenseed:

>> ^Ornthoroneriously, read the manifesto. Area = (tau/2) r^2 actually makes more sense, too.

Dude that manifesto is fucking hilarious...all of this math knowledge spouted and all for what? All because he doesn't like doing fractions??? Really??? Yea let's rewrite all the math texts since before Princia Mathematica just so you can use tau/6 instead of pi/12. That's useless knowledge wasted on somebody with no common sense. Furthermore, it adds unnecessary fractions in things like Euler's identity and like what you just pointed out, the area of a circle.

Well, it's certainly unrealistic to expect that we can get rid of pi in favour of tau after over two millenia of pi's monopoly. But one can dream, can't one?

>> ^Ornthoron:

Seriously, read the manifesto. Area = (tau/2) r^2 actually makes more sense, too.


Dude that manifesto is fucking hilarious...all of this math knowledge spouted and all for what? All because he doesn't like doing fractions??? Really??? Yea let's rewrite all the math texts since before Princia Mathematica just so you can use tau/6 instead of pi/12. That's useless knowledge wasted on somebody with no common sense. Furthermore, it adds unnecessary fractions in things like Euler's identity and like what you just pointed out, the area of a circle.

>> ^rottenseed:

There are a lot of discrete mathematical (series) implications to pi as well. I believe that's what standardized the use of pi being pi and not being 2 pi.
In fact, geometrically, beyond trig, if you look at areas and circumferences your options would be looking at the alternative function of area=(pi/2) r^2 instead of just (pi) r^2. Now would it be easier to have 2 variables, tau and pi and remember when to switch between the 2? No. Really, learning basic trig would be the only advantage of this...which is a minute part of the math world.

Seriously, read the manifesto. Area = (tau/2) r^2 actually makes more sense, too.

There are a lot of discrete mathematical (series) implications to pi as well. I believe that's what standardized the use of pi being pi and not being 2*pi.

In fact, geometrically, beyond trig, if you look at areas and circumferences your options would be looking at the alternative function of area=(pi/2)*r^2 instead of just (pi)*r^2. Now would it be easier to have 2 variables, tau and pi and remember when to switch between the 2? No. Really, learning basic trig would be the only advantage of this...which is a minute part of the math world.

The Tau Manifesto
Michael Hartl
http://tauday.com


Vi Hart — Blog
http://vihart.com/

I am a recreational mathemusician currently living on Long Island, NY.

I like most creative activities that involve making a lot of noise, mess, or both. Aside from composing, I love improvising on various instruments, drawing, sculpting, and other methods of making things. My main hobby is mathematics, with special interests in symmetry, polyhedra, and surreal complexity. This usually manifests as collaborative research in computational geometry and other areas of theoretical computer science, or as mathematical art. I think the human brain is incredible and strange, so I have developed a great interest in dreaming and consciousness. As a result, I am a trained hypnotist and a lucid dreamer. The human body is pretty neat as well, so I enjoy dancing and judo. I always love to learn new things—variety is the food of creativity!
You can email me at vi (at) vihart.com.
If you'd like to leave me voicemail or send me an SMS, call or text (+1) 530‑7VI‑HART [530‑784‑4278].

>> ^BoneRemake:

"Euler's Disk" is a trademark for a product manufactured and distributed by the "Damert Company" (Toysmith Group), consisting of a metal disk, a base having an upwards-facing concave mirror, and holographic, patterned magnetic stickers. One or more magnetic stickers may be attached to the top surface of the disk. The disk, when spun on the mirror, exhibits a spinning/rolling motion. Euler’s Disk has an optimized aspect ratio and precision polished, rounded edges to maximize the spinning/rolling time. A coin spun on a table, or any disc spun on a relatively flat surface, exhibits essentially the same type of motion.
A spinning/rolling disk ultimately comes to rest; and it does so quite abruptly, the final stage of motion being accompanied by a whirring sound of rapidly increasing frequency. As the disk rolls, the point P of rolling contact describes a circle that oscillates with a constant angular velocity ω. If the motion is non-dissipative, ω is constant and the motion persists forever, contrary to observation (since ω is not constant in real life situations).
In the April 20, 2000 edition of Nature, Keith Moffatt shows that viscous dissipation in the thin layer of air between the disk and the table is sufficient to account for the observed abruptness of the settling process. He also showed that the motion concluded in a finite-time singularity.
Moffatt shows that, as time t approaches a particular time t0 (which is mathematically a constant of integration), the viscous dissipation approaches infinity. The singularity that this implies is not realized in practice because the vertical acceleration cannot exceed the acceleration due to gravity in magnitude. Moffatt goes on to show that the theory breaks down at a time τ before the final settling time t0, given by
\tau\simeq\left(2a/9g\right)^{3/5} \left(2\pi\mu a/M\right)^{1/5}
where a is the radius of the disk, g is the acceleration due to Earth's gravity, μ the dynamic viscosity of air, and M the mass of the disk. For the commercial toy (see link below), τ is about 10 − 2 seconds, at which \alpha\simeq 0.005 and the rolling angular velocity \Omega\simeq 500\rm Hz.
Using the above notation, the total spinning time is
t_0=\left(\frac{\alpha_0^3}{2\pi}\right)\frac{M}{\mu a}
where α0 is the initial inclination of the disk. Moffatt also showed that, if t0 − t > τ, the finite-time singularity in Ω is given by.....
http://en.wikipedia.org/wiki/Euler%27s_disk


Nerd.

"Euler's Disk" is a trademark for a product manufactured and distributed by the "Damert Company" (Toysmith Group), consisting of a metal disk, a base having an upwards-facing concave mirror, and holographic, patterned magnetic stickers. One or more magnetic stickers may be attached to the top surface of the disk. The disk, when spun on the mirror, exhibits a spinning/rolling motion. Euler’s Disk has an optimized aspect ratio and precision polished, rounded edges to maximize the spinning/rolling time. A coin spun on a table, or any disc spun on a relatively flat surface, exhibits essentially the same type of motion.

A spinning/rolling disk ultimately comes to rest; and it does so quite abruptly, the final stage of motion being accompanied by a whirring sound of rapidly increasing frequency. As the disk rolls, the point P of rolling contact describes a circle that oscillates with a constant angular velocity ω. If the motion is non-dissipative, ω is constant and the motion persists forever, contrary to observation (since ω is not constant in real life situations).

In the April 20, 2000 edition of Nature, Keith Moffatt shows that viscous dissipation in the thin layer of air between the disk and the table is sufficient to account for the observed abruptness of the settling process. He also showed that the motion concluded in a finite-time singularity.

Moffatt shows that, as time t approaches a particular time t0 (which is mathematically a constant of integration), the viscous dissipation approaches infinity. The singularity that this implies is not realized in practice because the vertical acceleration cannot exceed the acceleration due to gravity in magnitude. Moffatt goes on to show that the theory breaks down at a time τ before the final settling time t0, given by

\tau\simeq\left(2a/9g\right)^{3/5} \left(2\pi\mu a/M\right)^{1/5}

where a is the radius of the disk, g is the acceleration due to Earth's gravity, μ the dynamic viscosity of air, and M the mass of the disk. For the commercial toy (see link below), τ is about 10 − 2 seconds, at which \alpha\simeq 0.005 and the rolling angular velocity \Omega\simeq 500\rm Hz.

Using the above notation, the total spinning time is

t_0=\left(\frac{\alpha_0^3}{2\pi}\right)\frac{M}{\mu a}

where α0 is the initial inclination of the disk. Moffatt also showed that, if t0 − t > τ, the finite-time singularity in Ω is given by.....

http://en.wikipedia.org/wiki/Euler%27s_disk

>> ^gwiz665:

>> ^gorillaman:
>> ^xxovercastxx:
There really aren't any good guys in WH40K, though I'd say the Eldar are the most innocent.
>> ^gorillaman:
Also, the Imperium are not the good guys.


Exactly, though the Eldar are as xenophobic and ruthless as anyone else. The Tau are the obvious candidates as heroes - they're young, innovative, and they've got that underdog thing going, almost an idealised, progressive human race; but look closer and they're an ultra-communist slave society, aggressive and coercive in getting other races to join their Empire. If any race can claim innocence it can only be the Orks. They just dig fighting, and don't understand that other people don't like having their limbs hacked off.

Necrons are the only good guys.
"You can die, or you can run then die."


Aw, all Necrons want is to regain their galaxy of simple purity. Or rather I should say, all the C'Tan want. At least they want to exterminate Chaos.

>> ^gorillaman:

>> ^xxovercastxx:
There really aren't any good guys in WH40K, though I'd say the Eldar are the most innocent.
>> ^gorillaman:
Also, the Imperium are not the good guys.


Exactly, though the Eldar are as xenophobic and ruthless as anyone else. The Tau are the obvious candidates as heroes - they're young, innovative, and they've got that underdog thing going, almost an idealised, progressive human race; but look closer and they're an ultra-communist slave society, aggressive and coercive in getting other races to join their Empire. If any race can claim innocence it can only be the Orks. They just dig fighting, and don't understand that other people don't like having their limbs hacked off.


Necrons are the only good guys.

"You can die, or you can run then die."

>> ^xxovercastxx:

There really aren't any good guys in WH40K, though I'd say the Eldar are the most innocent.
>> ^gorillaman:
Also, the Imperium are not the good guys.


Exactly, though the Eldar are as xenophobic and ruthless as anyone else. The Tau are the obvious candidates as heroes - they're young, innovative, and they've got that underdog thing going, almost an idealised, progressive human race; but look closer and they're an ultra-communist slave society, aggressive and coercive in getting other races to join their Empire. If any race can claim innocence it can only be the Orks. They just dig fighting, and don't understand that other people don't like having their limbs hacked off.

Redgum:I Was Only Nineteen
From LyricWiki
This song is performed by Redgum.

This song has been covered under the title I Was Only 19 by The Herd.

Mum and Dad and Denny saw the passing-out parade at Puckapunyal
It was a long march from cadets.
The sixth battalion was the next to tour, and it was me who drew the card.
We did Canungra, and Shoalwater before we left.

And Townsville lined the footpaths as we marched down to the quay
This clipping from the paper shows us young and strong and clean.
And there's me in my slouch hat with me SLR and greens.
God help me, I was only nineteen.

From Vung Tau, riding Chinooks, to the dust at Nui Dat -
I've been in and out of choppers now for months.
But we made our tents a home, VB and pinups on the lockers
And an Asian orange sunset through the scrub.

And can you tell me, doctor, why I stil can't get to sleep?
And night-time's just a jungle dark, and a barking M16?
And what's this rash that comes and goes, can you tell me what it means?
God help me, I was only ninteen.

A four week operation when each step could mean your last one on two legs.
It was a war within yourself.
But you wouldn't let your mates down 'til they had you dusted off,
So you closed your eyes and thought about something else.

Then someone yelled out "Contact!" and the bloke behind me swore.
We hooked in there for hours, then a God-almighty roar.
And Frankie kicked a mine the day that mankind kicked the moon,
God help me, he was going home in June.

I can still see Frankie drinking tinnies in the Grand Hotel
On a thirty-six hour rec leave in Vung Tau.
And I can still hear Frankie lying screaming in the jungle
Til the morphine came and killed the bloody row.

And the Anzac legends didn't mention mud and blood and tears.
And the stories that my father told me never seemed quite real.
I caught some pieces in my back that I didn't even feel.
God help me, I was only nineteen.

And can you tell me, doctor, why I still can't get to sleep?
And why the Channel Seven chopper chills me to my feet?
And what's this rash that comes and goes, can you tell me what it means?
God help me, I was only nineteen.