1. tape measure (for showing ratio) Pi book prize (for most pi digits)
Bring:
big cylinder
string
tape measure (for showing ratio)
Pi book
prize (for most pi digits)
test computer sound
Next slide to start...

2. p
Pi, one of the fundamental numbers in mathematics, science and engineering
Defined as the ratio of the circumference to the diameter of a circle
(Demo with string and tape measure that C = 3*D)
Approximately =
Pops its head up in engineering equations, particularly anything involving cycles (1 Hz = 2*pi rad/sec)

4. r x?
Draw a square with the same area as a circle using nothing other than a straightedge and a compass
Cannot be done. Neither can one calculate the quantity (circumference/diameter)
People have tried for 4000 years
Pi is an irrational number; never repeats, never ends. Proved irrational in 1794.
x = r √π

5. The earliest record r Egyptian scribe Ahmes, 1650 B.C.
“Cut 1/9 off diameter and make the rest one side of a square. That square will have same area as the circle”
p = …
Good to 1% (1 digit)
x = 8/9 d
Interest in pi has existed since earliest times
X = 8/9 d = 16/9 r
16/9 ~ sqrt(pi)
(16/9)^2 ~ pi
~ pi r

6. Notable Archimedes (Greece, ~200 B.C.)
p is between 3-1/7 and 3-10/71, 2 digits
Tsu Ch’ung-chih (China, ~400 A.D.)
p = 355/113, 6 digits
Viete (Italy, 1579)
10 digits
Euler (Switzerland, ~1780)
20 digits
Leibniz (founder of calculus) 1675, came up with very inefficient calculation formula. Newton, the other founder of calculus had a much better formula.
First calculation of pi with a computer: ENIAC, Aberdeen Proving Grounds, 19,000 vacuum tubes, 2,037 digits in 70 hours
Tamura and Kanada (Japan, 1982) 8,388,608 digits in 7 hours

7. Guess what you think is the current record?3.
12,000 digits
Guess what you think is the current record?

8. 1.24 trillion Kanada (Japan, 2002)
Current record for calculation of digits
Kanada (Japan, 1999) , 206 billion

9. David and Gregory Chudnovsky
Brothers, mathematicians and number theorists
Held record several times: 450 million, 1 billion, 2 billion, 8 billion
Hackers, built home-brew supercomputers in their NYC apartment
“Institute for Mathematics and Advanced Supercomputing” at Brooklyn Polytech. Just those two.

10. Engineering approximations for p
Engineers need 1 or 3 or 7 digits. Physicists need 15

11. The bible weighs in
Also he made a molten sea of 10 cubits from brim to brim, round in compass, and five cubits the height thereof; and a line of 30 cubits did compass it round about
From Joy of Pi
Proof that pi = 3?
For most rough calculations, pi = 3 is fine
Let’s go to the real experts (Simpsons)
1 Kings 7:23

12. "Bye Bye Nerdy" CABF11 Original Airdate: 3/11/01
Lisa tries to befriend a new student, only to become the target of the girl's violent outbursts. When the bully, Francine, beheads Malibu Stacey, Lisa vows to get to the root of the problem. After scientific research on typical bully targets (i.e. nerds), Lisa discovers that it's the nerd scent that sets off Francine and the other school bullies. Lisa invents an antidote and is hailed a heroine by geeks everywhere.

14. Memorizing pi Can you remember your SSN (9 digits)?
Can you remember your student id (10 digits)?
Can you remember a credit card number (16 digits)?
How many do you know?
Whose got it to 4 digits? To 10? More?
Prize to winner

15.
31 digits
Alexander Aitken (Univ of Edinburgh) 1,000 digits
Simon Plouffe (1975) 4,096 digits
Rajan Mahadevan (1983) 31,811 digits

16. The record 42,000 digits Hiroyuki Goto, 1995
Tie to text (length of words) “How I wish I could calculate pi” ( )
Or, musical notes

17. MIT football cheer…
E to the U du dx, E to the X dx. Cosine, secant, tangent, sine, Integral radical mu dv Slipstick, sliderule, MIT!
On the web site it was

18. A small window to help you appreciate this fabulous number.
Now how about e? Or, sqrt(2)?!!