### The Pi versus Life Of Pi

I am sure most of you have watch the movie ‘Life Of Pi’ (trailer below), which depicts the power of life’s force and the human desire for companionship. Is it a true story ? Majority of people doubts that or even just brush-off. Go watch the movie if you haven’t.

In real life, Pi (π) is a very important constant in mathematics. You need it to calculate the area of a circle or the volume of a cylinder or sphere. It is an irrational number, meaning that it cannot be expressed exactly as a fraction or a decimal number, because it has *no ending decimal digits and you can’t find a valid repeat pattern*.*

In the fifth century, a Chinese astronomer and mathematician Zu Chong Zhi calculate and estimates Pi as 355/113, a remarkable accuracy for the standard at that time, more accurate than 22/7 lazily used today and this number was used worldwide for the next 1000 years !

Today, modern computers easily compute Pi up to trillion decimal places. The first 101 digits of Pi is 3.1415926535 8979323846 2643383279 5028841971 6939937510 5820974944 5923078164 0628620899 8628034825 3421170679

In 2004, Englishman Daniel Tammet recites Pi from memory to 22,514 decimal places at the University of Oxford on Mar 14, 2004.

In 2005, Chinese student Chau Lu (24-year-old graduate from Northwest Agriculture and Forestry University in Shaanxi Province) recites Pi from memory to 67,890 decimal places without an error on Nov 20, 2005 and was recognized by Guinness World Records.

In 2006, Akira Haraguchi, a 59-year-old retired Japanese engineer, recites Pi from memory to 100,000 decimal places on Oct 4, 2006 but was not yet recognized by Guinness World Records.

In 2010, Shigeru Kondo, a Japanese systems engineer and Alexander Lee, an American computer science student, use a single desktop computer to compute Pi up to 5 trillion decimal places. It took them 90 days to do that.

*unlike 3/7, which is a rational fraction, it’s decimal numbers repeat with the pattern 428571

(3/7 = 0.428571 428571 428571 428571 428571 …….)

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