Pi miscalculated or not irrational?

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    Irrational Pi
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Discussion Overview

The discussion revolves around the nature of pi, specifically questioning whether it is miscalculated or if it is indeed an irrational number. Participants explore the implications of computer calculations of pi's digits and the relationship between real-life circles and the mathematical concept of pi.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant questions if the extensive calculation of pi's digits implies it is irrational, suggesting a potential misunderstanding of what irrationality means.
  • Another participant asserts that the calculation of digits does not determine irrationality, using the example of 1/3 to illustrate that many rational numbers can have long decimal expansions.
  • Some participants reference historical proofs of pi's irrationality, mentioning Euler and Lindemann, but there is some confusion regarding who first proved it.
  • A participant suggests that the imperfections of real-life circles do not imply that pi has been miscalculated, arguing that the algorithms for calculating pi do not rely on physical measurements of circles.
  • There is a mention of a demonstration of pi's irrationality found in Spivak's Calculus, indicating that there are educational resources available on the topic.
  • One participant clarifies that being transcendental means not being algebraic, linking it to the discussion of pi's properties.

Areas of Agreement / Disagreement

Participants express differing views on the implications of calculating pi's digits and the historical context of its proofs. There is no consensus on the relationship between real-life circles and the calculation of pi, nor on the specifics of its proofs.

Contextual Notes

There are unresolved points regarding the historical attribution of the proof of pi's irrationality and the implications of real-world measurements on the mathematical concept of pi.

Mr. X
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pi miscalculated or not irrational?

I know that computers have calculated thousands of digits of pi, but does this mean that pi is an irrational number? How can we be so sure that it is irrational? And I have one more question. The circles we see in real life are not perfect circles. Does this mean that pi might have been miscalculated? :confused: :confused: :confused:
 
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I know that computers have calculated thousands of digits of pi, but does this mean that pi is an irrational number?

No, we can calculate thousands of digits of the decimal expansion of 1/3, but that doesn't make it irrational ;)

How can we be so sure that it is irrational?

Because it was proven (way back in 1768, if my googling is correct). See http://www.mcs.csuhayward.edu/~malek/Mathlinks/Pi.html page for a proof.

The circles we see in real life are not perfect circles. Does this mean that pi might have been miscalculated?

No, why would it mean that? I /seriously/ doubt that any of the algorithms used for calculating millions of digits of pi include any measurements of "real" circles...

You might find this page interesting. As you can see, most of those formulas are quite far removed from anything concerning circles (other than the fact that they involve pi, of course)...
 
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As Muzza said, Euler proved that pi is irrational.
It was proved to be transcendental by Lindemann in the 19th century, I believe
 
As Muzza said, Euler proved that pi is irrational.

I didn't say that... ;) Mathworld says that it was Lambert who proved it.

It appears as if the date I gave in my last post was wrong.
 
A really neat demostration of the fact tha Pi is irrational can be found in Spivak's Calculus
 
arildno said:
As Muzza said, Euler proved that pi is irrational.
It was proved to be transcendental by Lindemann in the 19th century, I believe

to be trascendental is the same thing that to be not algebraic, isn't it?
 
Yes. (This is just a filler to get rid of the silly "you can't post a message this short"-error).
 
Yes indeed.
 

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