## Pi Day Is Coming — But Tau Day Is Better 241

Posted
by
Soulskill

from the circular-logic dept.

from the circular-logic dept.

PerlJedi writes

*"A few months ago, a Tweet from Randal Schwartz pointed me to a YouTube video about 'Triangle Parties' made by Vi Hart. My nerdiness and my love of math made it my new favorite thing on YouTube. Now, with Pi Day coming up later this week, I thought it would be an appropriate time to point people to another of her YouTube videos: Pi is Wrong. The website she mentions at the end, Tauday, has a full explanation of the benefits of using Tau rather than Pi. Quoting: 'The Tau Manifesto is dedicated to one of the most important numbers in mathematics, perhaps the most important: the circle constant relating the circumference of a circle to its linear dimension. For millennia, the circle has been considered the most perfect of shapes, and the circle constant captures the geometry of the circle in a single number. Of course, the traditional choice for the circle constant is pi — but, as mathematician Bob Palais notes in his delightful article "Pi Is Wrong!", pi is wrong. It's time to set things right.'"*
## Re:tau is wrong (Score:3, Informative)

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

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

## Re:Seems pretty unimportant (Score:2, Informative)

But, my point is, it depends on the equation. Some might look simpler, some might not.

IMO, TFA is cherry picking. I'm sure there's a whole list of equations that would suddenly introduce new factors of 1/2 or 0.5, which most would consider more annoying than a 2.

For instance, the area of a circle would be (1/2)tau*r^2 - which seems a bit awkward to me. Since tau = C/r, You could simplify it to (C*r)/2, but again - fractions are awkward to write, especially with a keyboard, and mistakes get easy to make. I like PI*r^2, myself.

There may exist equations in which inserting your 13's and 59s simplify the math, in which case a good old "let banana = 13/59 * pi" might make your paper more readable.

To call any number "right" or "wrong", is a bit stupid.

## Re:tau is wrong (Score:4, Informative)

No it isn't. It completely misses the point of e^(pi * i) = -1, which is that the left side gives you a bloody negative number.

The tau version is rather obvious, since you are squaring (-1). Put it another way, if e^(pi * i) had happened to equal 1, the tau version would be exactly the same. The tau version doesn't really tell you what is special about Euler's identity.