# Pi Digits, Pi-oetry, and Anti-Pi

This week’s Math Munch is brought to you by the number pi, because Wednesday (March 14th) is Pi Day!

Pi is an irrational number – meaning that it cannot be written as a ratio of integers.  Consequently, it’s decimal expansion goes on and on forever without any repeats.  But, that doesn’t mean people haven’t tried to list as many digits of pi as they can!  This site lists the first million digits of pi.  This site sings many of them – the tune is rather catchy.  And here you can search for strings of numbers in the decimal expansion for pi!  I searched for my birthday, 10/01/87 – it occurs 885,826 digits after the decimal point!

Remember the alphametics puzzle creator, Mike Keith?  Well, he writes poems and short stories in what he calls “Pilish,” in which the lengths of successive words represent successive digits of pi.  Here’s an explanation of the different forms of Pilish.  Mike holds the world record for the longest and second longest texts written in Pilish – they are his book, Not A Wake, and a short story, “Cadaeic Cadenza.”

Finally, as we celebrate pi on Wednesday, we should do so with some skepticism.  In the opinion of some mathematicians, pi is the wrong constant.  Inspired by this article by mathematician Bob Palais, some people have been speaking up in favor of the constant tau, which is double pi.  Here’s our favorite Vi Hart on the issue of pi:

You’ve heard what pi sounds like.  Want to know what tau sounds like?

Bon appetit!

### 8 responses »

1. a clip from a BBC documentary on savant Daniel Tammet in which he recalls the first 20,000 or so digits of pi. Very interesting fellow. Later in the profile they test him on his claim to be able to learn an entirely new language in only a week’s time.

2. Tau takes memorizing the radians of a circle completely out of the picture. Instead of spending time worrying about how to get the right radians when solving trig functions and graphing, students would be able to focus more on the concepts of why we graph trig functions the way we do, and how the formulas are derived. I’m confused how she was able to take Euler’s formula and translate it to using Tau. Because pie is in the exponent, I wouldn’t think you would be able to throw in Tau, which equals 2 x pie, then get equal to -1. Is this kind of switch from pie to Tau possible for all equations involving pie?

• Hi, Gina! That’s a good question. I think you can switch from pi to tau in equations involving pi– so long as you replace pi with tau/2. But I can imagine there being some situations in which that might not work so well– especially if you don’t want a fraction exponent, such as in Euler’s formula. I bet you could do some research about this! If you find out anything, let us know!

3. I never thought about how pi makes no sense for all trig work. After watching this video i realized how useless pi is and why people just didn’t make it tau in the first place. Math is being over-complicated and tau would help simplify it. Someone should start a campaign to start teaching tau in school.