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A formula for the nth digit of πœ‹ and πœ‹^n

arxiv.org

101–110 of 143 posts

Re: A formula for the nth digit of πœ‹ and πœ‹^n

#101
post #35

Earlier quoted context omitted.

That would make it a rational number, so we can rule that out

Exactly, the only possible "last digit" it could have (in keeping with the silly premise that it has one), is zero.

The only possible "last digit" it could not have is zero: if the last digit were to be a zero, that digit would be superfluous and could be discarded, making the digit before that the real "last digit".

Proof: the first digit of pi is 3, not zero.

Re: A formula for the nth digit of πœ‹ and πœ‹^n

#104
post #93

Earlier quoted context omitted.

Yes, it looks like you're right. But I don't understand the reasoning - is he actually saying you can use this formula to compute pi^n to n decimal places? So it doesn't produce arbitrary digits on their own, but excellent approximations to pi^n? And this was by taking 4 terms of the zeta function infinite product expansion. 2xn digits would presumably be given by taking more terms (but quite a few, one for every pri…

Yeah, my sense is that the author knows this is more of a neat trick than a "practical" way of calculating pi. There's a bit on page 5 about how the Chudnovsky method totally blows this approach out of the water.

Seems like the real breakthrough was computing large Bernoulli numbers without a very precise value for pi, and this is a relatively easy corollary for someone to spot and get a paper out of.

Re: A formula for the nth digit of πœ‹ and πœ‹^n

#105

See also Plouffe's earlier (1995) formula to extract hexadecimal digits of pi: https://en.m.wikipedia.org/wiki/Bailey%E2%80%93Borwein%E2%80...

We should also have decimal/binary/hex digits of Tau to complete the set.

Decimal is the only tricky one. Given that tau=2pi, simple use f(n-1) in the original binary formula for pi, and I’m sure something just as trivial for hex.

Re: A formula for the nth digit of πœ‹ and πœ‹^n

#106

See also Plouffe's earlier (1995) formula to extract hexadecimal digits of pi: https://en.m.wikipedia.org/wiki/Bailey%E2%80%93Borwein%E2%80...

...which Fabrice Bellard improved upon: https://en.m.wikipedia.org/wiki/Bellard%27s_formula

Re: A formula for the nth digit of πœ‹ and πœ‹^n

#107
post #53
post #52

Earlier quoted context omitted.

If you can download it from arxiv, it is published. Researchers don’t really care whether the paper went through formal peer review and publication process in some journal, because that process is of little value: they can figure out that the author meant rank instead of rand etc.

"Published" in this context is short for "published to a journal" or more completely for this thread "gone through the full edit cycle you would expect from a paper published to a journal". For example, https://arxiv.org/help/jref says: > When a article is published, the author may wish to indicate this in the abstract listing for the article. For this reason, the journal reference and DOI (Digital Object Identifier)…

Don't abbreviate unless you have great confidence that everyone hearing or reading your words shares the same dictionary.

Re: A formula for the nth digit of πœ‹ and πœ‹^n

#108
post #101

Earlier quoted context omitted.

Exactly, the only possible "last digit" it could have (in keeping with the silly premise that it has one), is zero.

The only possible "last digit" it could not have is zero: if the last digit were to be a zero, that digit would be superfluous and could be discarded, making the digit before that the real "last digit". Proof: the first digit of pi is 3, not zero.

sigh It was said in jest, in response to another comment also said in jest.

That aside, the apparent "empty space" on the either side of a number is in reality consisting of infinite zeroes.

Just because we typically choose to "display" most numbers without those zeroes, it doesn't mean they aren't there in a very real, practical and important sense.

They are there, because if they aren't there, then something else might be, and then all our numbers would have to be assumed to be wrong or incomplete... so instead, we assume the zeroes.

The terrible reality is the zeroes extend off infinitely in either direction, and we use empty space as shorthand for this so we don't have to spend longer than the age of the universe to write a single number with full accuracy.

Re: A formula for the nth digit of πœ‹ and πœ‹^n

#109
post #52

Earlier quoted context omitted.

If you can download it from arxiv, it is published. Researchers don’t really care whether the paper went through formal peer review and publication process in some journal, because that process is of little value: they can figure out that the author meant rank instead of rand etc.

There is definitely a difference between "public(ly available on arxiv)" and "published (in a peer-reviewed journal)". Depending what I want to do I may prefer on or the other for my work as a researcher.

Sure, but if the paper is never published in a journal, and just exist as a pdf on arxiv forever, you won’t treat it any different than if it was published. You’ll still ignore it if it looks crap, still read it if it looks promising, still tell your friends about it if it has interesting results, still cite it etc. In short, it doesn’t matter much if the paper was formally published.

Re: A formula for the nth digit of πœ‹ and πœ‹^n

#110
post #53
post #52

Earlier quoted context omitted.

If you can download it from arxiv, it is published. Researchers don’t really care whether the paper went through formal peer review and publication process in some journal, because that process is of little value: they can figure out that the author meant rank instead of rand etc.

"Published" in this context is short for "published to a journal" or more completely for this thread "gone through the full edit cycle you would expect from a paper published to a journal". For example, https://arxiv.org/help/jref says: > When a article is published, the author may wish to indicate this in the abstract listing for the article. For this reason, the journal reference and DOI (Digital Object Identifier)…

I understand what it means, which you could have seen by reading my comment carefully. My point is that this publication process is of little value these days.
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