Happy Tau Day!

Have you ever wondered why it takes two \pi to go only one turn around a pie?  Or why everywhere in math you see:

e^{2\pi i} = 1

Euler’s Equation


Cauchy's integral formula


The Gaussian Distribution (aka the Bell Curve)


Stirling's Formula for approximating the factorial function

Looking at the $\latex \pi$’s in math, you’ll start to notice that more often than not, there are two \pi‘s, not just one.

People being what they are, they have gotten all ideological about it.   They’ve defined

\tau = 2\pi.

Here \tau stands for “t”, as in “turn”, as in one \tau is one turn of the circle.  There is a movement afoot to use \tau instead of \pi in math.   To the believers, today is \tau Day (which makes March 14th (1/2) \tau Day).  They have a manifesto, a website, a guru, media coverage, a T-shirt:

Every revolution needs a good T-shirt

an anthem :

and a local devotee.


One thought on “Happy Tau Day!

  1. Pingback: Pi Day in Pune! | OU Math Club

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