## Wednesday, March 14, 2007

### π Day

3.141592653589793238462643383279502884197169399375105820974944592307816406286208998628034825342117067982148086513282306647093844609550582231725359408128481117450284102701938521105559644622948954930381964428810975665933446128475648233786783165271201909145648566923460348610454326648213393607260249141273724587006606315588174881520920962829254091715364367892590360011330530548820466521384146951941511609...

I'm having p(ad tha)i for lunch. Not sure if I'll get any pie today though...

• The value of π has been known in some form since antiquity. As early as the 19th century BC, Babylonian mathematicians were using π = 25⁄8, which is within 0.5% of the true value.

• The Indian mathematician and astronomer Aryabhata in the 5th century gave the approximation π = 62832⁄20000 = 3.1416, correct when rounded off to four decimal places. He also acknowledged the fact that this was an approximation, which is quite advanced for the time period.

• The Chinese mathematician and astronomer Zu Chongzhi computed π to be between 3.1415926 and 3.1415927 and gave two approximations of π, 355⁄113 and 22⁄7, in the 5th century.

• Even long before computers have calculated π, memorizing a record number of digits became an obsession for some people. The current world record is 100,000 decimal places, set on October 3, 2006 by Akira Haraguchi. [3] The previous record (83,431) was set by the same person on July 2, 2005 [4], and the record previous to that (43,000) was held by Krishan Chahal.

• There are many ways to memorize π, including the use of piems, which are poems that represent π in a way such that the length of each word (in letters) represents a digit. Here is an example of a piem: How I need a drink, alcoholic in nature (or: of course), after the heavy lectures involving quantum mechanics. Notice how the first word has 3 letters, the second word has 1, the third has 4, the fourth has 1, the fifth has 5, and so on. The Cadaeic Cadenza contains the first 3834 digits of π in this manner.

• Swedish jazz musician Karl Sjölin once wrote, recorded and performed a song based on and called Pi. The song followed the decimals of Pi, with every number representing a certain note. For example 1=C, 2=D, 3=E etc. The song was then performed as a jazz song, thus making the harmony more liberal.

• On July 22, Pi Approximation Day is celebrated (22/7 - in European date format - is a popular approximation of π).

• It's also Albert Einstein's birthday!

Happy π Day everyone! Do something to make yourself a well-rounded human being today.