Is there a Whole Number Multiple of Pi Closest to a Whole Number?

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Discussion Overview

The discussion revolves around the question of whether there exists a whole number multiple of pi that is closest to a whole number. Participants explore the implications of this question, including theoretical aspects and numerical approximations.

Discussion Character

  • Exploratory
  • Technical explanation
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant, Daniel, poses the initial question about the existence of a whole number multiple of pi that is closest to a whole number and asks for proof.
  • Another participant asserts that there is no single solution to the problem, referencing Kronecker's density theorem, which suggests that multiples of pi can get arbitrarily close to an integer but can never equal one.
  • A later reply expresses curiosity about whether there is a pattern in the integers that bring multiples of pi closer to whole numbers, suggesting that certain irrational numbers exhibit such patterns.
  • One participant provides examples of rational approximations of pi, such as 22/7 and 333/106, and discusses their proximity to whole numbers when multiplied by their respective denominators.
  • A participant shares results from a computer program that identifies specific integers which, when multiplied by pi, yield results extremely close to integers, noting the limitations of achieving an exact integer result.

Areas of Agreement / Disagreement

Participants generally agree that while multiples of pi can approach whole numbers closely, no single multiple can equal a whole number. However, there is no consensus on the specific integers that yield the closest approximations.

Contextual Notes

The discussion includes references to mathematical theorems and approximations, but does not resolve the question of which integers provide the closest multiples of pi to whole numbers.

Who May Find This Useful

This discussion may be of interest to those exploring number theory, irrational numbers, and mathematical approximations, particularly in the context of pi.

danyo
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Hi everyone,

About 15 minutes ago I came up with a problem... What whole number multiple of pi would result in a number closest to a whole number?

Does a single whole number multiple exist, and can we... prove it?


Thanks for help in advance!


-Daniel
 
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danyo said:
Hi everyone,

About 15 minutes ago I came up with a problem... What whole number multiple of pi would result in a number closest to a whole number?

Does a single whole number multiple exist, and can we... prove it?


Thanks for help in advance!


-Daniel

There is no solution to that problem. The thing is that we can get n\pi as close to an integer as we like. This is basically Kroneckers density theorem. Of course, a nonzero multiple of \pi can never actually equal an integer (since that would imply that \pi is rational), but it can be arbitrary close.

The number \pi is not special here, it works for any irrational number.
 
micromass said:
There is no solution to that problem. The thing is that we can get n\pi as close to an integer as we like. This is basically Kroneckers density theorem.

Thank you for the reply, micromass! I was not familiar with Kronecker's density theorem, but its logic clarifies this problem. I wonder if there's any pattern in what integers n would bring us closer to a whole number...

Ah, well there goes my bedtime tonight! Thanks for the direction :D
 
danyo said:
I wonder if there's any pattern in what integers n would bring us closer to a whole number...
That is a much more interesting problem (to me). For certain types of irrational numbers, there is indeed a pattern (you can check out Pell's equation and Continued Fractions to find ways to very closely approximate square roots).

However, here is how you would find such integers for pi. We know the close approximation of 22/7 for pi. Then we have:

22/7≈pi
22≈7pi

And verifying, we have 7*pi≈21.99114858

Another close approximation is 333/106:

333/106≈pi
333≈106pi

and 106pi≈333.0088213...

I hope this proves useful!
 
You might also be interested in the following thread from the wu riddle site;

"Say I am given a number X = A*[sqrt]2 + B*[pi], where A and B are integers.
Given X, how can you find A and B, without using brute force?"

It comes with a long discussion.

see
http://www.ocf.berkeley.edu/~wwu/cgi-bin/yabb/YaBB.cgi
 
I ran a quick computer program just for interest sake.

78256779
103767361
129277943
131002976
156513558
180299107
182024140
183749173
205809689
207534722
209259755
233045304
234770337
236495370
258555886
260280919
262005952

Those numbers if multiplied with pi will give you a number so close to a integer that the decimal part can't fit in a double precision floating point. As stated above you can't actually get a integer from multiplying a integer with pi (except 0)
 

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