Tau

Tau, denoted $\tau$ , is most commonly used as 2 $\pi$ (see Pi if you are part of the minority of the AoPS community which does not know what $\pi$ is). For a convincing proof that $\tau$ is a better circle constant than $\pi$ , see The Tau Manifesto by Michael Hartl. This following section will summarize one main point of the Tau Manifesto.

Why $\tau$ Is Better Than $\pi$

Have you ever been in geometry class and been asked to graph sine waves with their ridiculous extra factor of 2 in the x-axis? Have you ever thought radian angle measure was hopelessly tainted with the superfluous and yet unavoidable factor of 2 (There are 2 $\pi$ radians in a full revolution)? $\tau$ resolves that. One $\tau$ is one revolution. Simple as that. While you have to remember that $\frac{\pi}{8}$ radians is NOT $\frac{1}{8}$ of a revolution, but is equal to $\frac{1}{16}$ of a revolution because of that idiosyncratic factor of 2, $\frac{\tau}{8}$ radians is just $\frac{1}{8}$ of a revolution. Likewise, $\frac{\tau}{3}$ radians is just $\frac{1}{3}$ of a revolution, $9001\tau$ radians is just 9001 revolutions, $123456789\tau$ radians is just 123456789 revolutions, and $x\tau$ radians is $x$ revolutions for any real $x$ .