Pi, the long way around

ryos · 2006-04-23 15:04:00

The blogger "ridiculous fish" has implemented a very novel approach to cutting out comment spam (and much better than the "distorted image" method). I thought it was both interesting and cool. Have a look:

http://ridiculousfish.com/blog/?p=23

Last edited by ryos (2006-04-23 15:04:19)

MathsIsFun · 2006-04-23 21:33:02

So far they have:
* 1359 / 2475 pairs were relatively prime.
* pi is approximately 3.30562434615

krassi_holmz · 2006-04-24 01:08:56

Pretty interesting.

krassi_holmz · 2006-04-24 01:35:19

Here's a Mathematica fuction which makes n tests with numbers less than b:

PPr[n_, b_] :=
  (
    c = 0;
    Do[If[GCD[Random[Integer, {1, b}], Random[Integer, {1, b}]] == 1, c++;], {i, 1, n}];
    c/n
    )

6/pi^2=0.607927

As you see, this method is unusable, because for approximately 3 digits of 6/pi^2 you need >10^6 tests.

Patrick · 2006-04-24 02:19:38

well, one million comments, that's not that much

He's just trying to make a laugh of spam (but ruining his fun is great too )

MathsIsFun · 2006-04-24 12:04:09

Good work, krassi!

Another (of the many) ways to calculate π would be to pick a random coordinate in a square, then see if it falls within the inscribed circle (using x²+y²=r²).

Math Is Fun Forum

#1 2006-04-23 15:04:00

Pi, the long way around

#2 2006-04-23 21:33:02

Re: Pi, the long way around

#3 2006-04-24 01:08:56

Re: Pi, the long way around

#4 2006-04-24 01:35:19

Re: Pi, the long way around

#5 2006-04-24 02:19:38

Re: Pi, the long way around

#6 2006-04-24 12:04:09

Re: Pi, the long way around

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