Irrational circles about the orgin

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Discussion Overview

The discussion revolves around the properties of circles centered at the origin with irrational or non-algebraic (transcendental) radii and their potential to pass through rational points. Participants explore theoretical implications and the nature of transcendental numbers in relation to geometry.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant recalls a previous discussion suggesting that a circle with an irrational radius can pass through a rational point if the radius is the square root of the sum of two rational squares.
  • Another participant proposes that if the radius is transcendental, the existence of a rational point on the circle would imply that the radius is algebraic.
  • Concerns are raised about the existence of transcendental numbers, with one participant expressing confusion about the possibility of traveling around a circle without encountering a rational point.
  • A clarification is made that non-algebraic numbers are equivalent to transcendental numbers in the context of real numbers.
  • One participant acknowledges that while algebraic irrational numbers are more numerous than transcendental numbers, this leads to the conclusion that a circle with a transcendental radius likely has no rational points on it.

Areas of Agreement / Disagreement

Participants express uncertainty regarding the existence of rational points on circles with transcendental radii, and there is no consensus on the implications of these properties. The discussion remains unresolved with competing viewpoints on the nature of transcendental numbers and their geometric implications.

Contextual Notes

Participants note the complexity of defining and understanding transcendental numbers and their relationship to rational points on circles, highlighting the need for further exploration of these concepts.

ramsey2879
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I recall a post previously where the Op was wondering if any circle about the orgin having an irrational radius could pass through a rational point. The answer then was if the irrational radius was the square root of the sum of two rational squares then of course.

Now I am wondering what if the radius was a non-algebraic number? Could that circle pass through a rational point?
 
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Hint: Suppose that r is transcendental and is the radius of a circle centered at the origin. Show that the existence of a rational point on this circle implies that r is algebraic.
 
Petek said:
Hint: Suppose that r is transcendental and is the radius of a circle centered at the origin. Show that the existence of a rational point on this circle implies that r is algebraic.
I was thinking that way but then I was wondering if transcendental numbers actually exist since it seems strange to me that one could travel a full circle and not come upon a rational point. Sorry but I have other things that I am working on and don't have time to look up the theory of transcendental numbers for now.
 
ramsey2879 said:
I was thinking that way but then I was wondering if transcendental numbers actually exist since it seems strange to me that one could travel a full circle and not come upon a rational point. Sorry but I have other things that I am working on and don't have time to look up the theory of transcendental numbers for now.

I'm honestly confused at this point. You used the term "non-algebraic number" in your original post. Non-algebraic numbers are exactly the same as transcendental numbers (if we're confining this discussion to real numbers). If I changed my hint to

Hint: Suppose that r is non-algebraic and is the radius of a circle centered at the origin. Show that the existence of a rational point on this circle implies that r is algebraic.[/color]

would that make more sense?
 
Yes I can see that x^2 + y^2 = r^2 would make r algebraic, but my real question was how can one move completely around a circle without passing over a rational point. Didn't that call into question the existence of non-algebraic values as real numbers?
PS, I took a look at some of the information of non-algebraic (transcendental) numbers and guess that they do exist. Moreover I noted that there are far more algebraic irrational numbers and transcendental numbers, so I guess that it must be true that such a circle has no rational point lying thereon.
 
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