"What Tau Sounds Like"
<a href="http://www.youtube.com/watch?v=3174T-3-59Q" rel="nofollow">http://www.youtube.com/watch?v=3174T-3-59Q</a><p>(Yes, we know that Tau doesn't <i>really</i> sound like anything, but this was fun and better than I expected.)
The earliest example I've seen of 2π is in a 1763 letter from Thomas Bayes (the paper that appeared in the Royal Society proceedings directly after the one that's famous). He used <i>c</i> for the circumference of a circle whose radius is unity.<p>If you've ever used Stirling's approximation, this is the paper that first points out that it's a divergent series.<p>Scan of original (it's also on JSTOR):
<a href="http://www.york.ac.uk/depts/maths/histstat/letter.pdf" rel="nofollow">http://www.york.ac.uk/depts/maths/histstat/letter.pdf</a><p>With modern typesetting and an explanation:
<a href="http://www.stat.ucla.edu/history/letter.pdf" rel="nofollow">http://www.stat.ucla.edu/history/letter.pdf</a><p>(I don't seriously think we should change from pi to tau.)
The most compelling argument for me in using tau, (and I have started trying to think in tau when it comes up) is the radians argument: one quarter of a circle is tau/4, or pi / 8, you pick.<p>I am certain my kids will have an easier time remembering tau/4, as I do myself.<p>The other compelling thing for me came from remembering just how many integrals from 0 to 2pi I wrote over my freshman complex analysis class. A lot. Less notation is always nice; having tau represent the entire circle just makes a lot of sense!
"Almost anything you can do in maths with pi you can do with tau anyway,"<p>WTF is this? I'm eagerly awaiting an explanation of what you can do with X that you can't do with 2X.<p>It's a moot anal point. X or 2Y, using one over the other doesn't solve anything.
The mathematical world is as full of lonely pi's, as it is of 2*pi's. Now we need to move to tau/2 and tau, only to get a pi-manifesto in a couple of decades.<p>Previous discussions:<p><a href="http://news.ycombinator.com/item?id=1468341" rel="nofollow">http://news.ycombinator.com/item?id=1468341</a><p><a href="http://news.ycombinator.com/item?id=2322666" rel="nofollow">http://news.ycombinator.com/item?id=2322666</a>
I started a Kickstarter to create a social object against Pi!<p><a href="http://www.kickstarter.com/projects/ianterrell/say-no-to-pi" rel="nofollow">http://www.kickstarter.com/projects/ianterrell/say-no-to-pi</a>
If it's not broken, don't fix it. I don't see pi broken as it has been used for _centuries_. Why should we change it all of a sudden? To signify that we're into a new era? The Tau era?
> Not all fans of maths agree, however, and pi's rich history means it will be a difficult number to unseat.<p>This statement is never supported (the fan part). Bad BBC, bad!
The Greek letter tau is already used to refer to the period of an oscillation, the time constant of a decay interval (these are intimately related), plus plenty of other stuff. There really aren't any Greek letters left that aren't used for a million things already. tau-as-time-constant is the standard use for the thing, and the confusion with torque and natural temperature is bad enough as it is.<p>Yes, pi shows up as the prime counting function, but there it's a <i>function</i>, which clears up the otherwise ambiguous notation. Furthermore these abuses of notation are generally considered a bad thing, something we try to avoid.<p>As for the intuitiveness of such deep results as Stirling's formula and the even values of the Riemann zeta: this is to concern oneself with the upholstery on the Space Shuttle.<p>If you want a new pi symbol, might I suggest the variant pi described here: <a href="http://en.wikipedia.org/wiki/Pi_%28letter%29" rel="nofollow">http://en.wikipedia.org/wiki/Pi_%28letter%29</a> -- though I'm afraid this is all a waste of time and energy.