Wednesday Is Pi Day

mrbluze points us to an AP writeup on the upcoming Pi Day — 3-14 (which some will observe at 1:59 pm). The article notes: "[T]he world record [for reciting the number Pi] belongs to Chao Lu, a Chinese chemistry student, who rattled off 67,890 digits over 24 hours in 2005. It took 26 video tapes to submit to Guinness," and mentions in passing a Japanese mental health counselor who last fall recited 100,000 digits, but did not choose to submit proof to the record book.

Re:Perhaps a typo?

[Patrik_AKA_RedX]

I have a near photographic memory for every useless trivial fact I come across. But when it comes to actual usefull stuff like math, or anything I'd need for an exam, then I've to do real trouble to actually get it to stick. Sometime I think my brain hates me or something.

1337

[HetMes]

Following the discussion about the date/time format, in continental Europe we proud ourselves in experiencing 13-3-7, or 1337...

Re:I live in Europe

[pryonic]

I've never understood the logic behind the American way of writing dates. I'm not trying to troll here, it just seems illogical to me.

Here at my office we use both the European and International numerican dates forms, depending on the sitation:

European: DD/MM/YYYY
International: YYYY/MM/DD

As you can the units of time (days, months, years) ascend or descend in order e.g. in the European format you go from the smallest unit (days) through the midsized (months) up to the largest (years). In the International format the same descends from largest first.

But with the American format you start with the month, then go to the smallest, then to the largest. It just seems totally illogical to me, anyone know why it's done that way?

Re:100000 digits?

[fLiXUs]

There are plenty of memory techniques. Didn't you know there is a world championship in remembering things? See for instance http://www.worldmemorychampionship.com/ [worldmemor...onship.com] or http://www.worldmemorychallenge.com/ [worldmemorychallenge.com].

If you want a tip, here's something a read in a book by a Norwegian memory world champion, Oddbjørn By:

1. Assign each 2 digit number to a person and an action related to that person. The person has two names, so the first character of each name represent one of the digits.
   
2. Now you can represent 4 digits with a person and an action. This will give you 4 with different first characters.
   
3. Imagine locations on a known path.
   
4. Assign a person doing an action at each location.
   
5. Now you have 4 digits per location on your path... Just make a very long path and you'll have 1,000,000 digits (250,000 locations*) in no time!
   
6. To recite the number, just traverse your path and look at the name of the person in each location, and the name of the person associated with the action.
   

*You probably want less locations, so you can visit the same one under different conditions. E.g. during day / night / rain / snow / heavy winds... we're down to 50,000 locations already!

Do they really recite the digits of pi?

[jmp]

I ask because when I was a child, I remember reading about the "reciting digits of pi" record in the family Guinness Book of Records. It had a photo of the then record-holder, standing in front of a chalk board, upon which was written "3.142857142857142857142857..."

It's not hard to recite the decimal expansion of 22/7.

Re:I live in Europe

[Anonymous Coward]

Nope. ISO mandates that you need the leading zero on months and days.

Re:I live in Europe

[MichaelSmith]

I think the French should have persisted with metric dates.

Re: You forgot: european format is yyyy.mm.dd

[muukalainen]

So you do get 3.14. Or, more preciselly, [2007.]3.14, but you can skip the first part.

Re:I live in Europe

[AliasMarlowe]

... but that Pi day was more than 4 centuries ago: 31.4.1593

Re:I live in Europe

[Saib0t]

it's more likely that the way it is said is a result of the way it is written, not the other way around...

Well, I beg to disagree... Speech comes before writing. And before knowing how to spell something, the word has been pronounced. With maybe the exclusion of the "new" language that originates from the internet where no word is spoken but typed.

Not really

[DavidShor]

If I assume that pi is normaly distributed in an arbitrary base b(widely believed), then the probability that the digits of pi will be pallindrimic after 2*n digits is the probability that an arbitraty string of length n with b letters will be picked(A arbitrary string appears, it must be repeated). This probability is 1/b^n. For odd legth sequences 2*n+1, n digits are picked, any digit can go in the middle, and the n sequence must be repeated. Because there are b ways to pick the middle digit, the probability will be b/b^n=1/b^(n-1).

So lets sum from n=1 to infinity 1/b^n. Basic Calculus returns a value of 1/(b-1)
This is the probability that the partial digits of pi will be a pallindrome, for base 10, the probability is 1/9. Though it is almost certainly true for binary.

For the existence of a odd length Pallindrome, I exclude the trivial singleton of length one. So as from two to infinity. This comes out to 1/(b-1).