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#1 2006-04-24 13:04:00

ryos
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Pi, the long way around

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 (2006-04-24 13:04:19)

El que pega primero pega dos veces.

#2 2006-04-24 19:33:02

MathsIsFun

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Re: Pi, the long way around

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

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

#3 2006-04-24 23:08:56

krassi_holmz
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Re: Pi, the long way around

Pretty interesting.

IPBLE:  Increasing Performance By Lowering Expectations.

#4 2006-04-24 23:35:19

krassi_holmz
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Re: Pi, the long way around

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

Code:

```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.

IPBLE:  Increasing Performance By Lowering Expectations.

#5 2006-04-25 00:19:38

Patrick
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Re: Pi, the long way around

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 )

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#6 2006-04-25 10:04:09

MathsIsFun

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Re: Pi, the long way around

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).

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman