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   Author  Topic: Integer Polynomial  (Read 511 times)
JP05
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Integer Polynomial  
« on: Aug 10th, 2006, 12:42pm »
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Let K,R,N be integers. Prove that 2^(1/2) K^2 - R pi^2 + N = 0 has no solutions.
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JP05
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Re: Integer Polynomial  
« Reply #1 on: Aug 10th, 2006, 12:47pm »
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Correction: Let K,R,N be integers > 0.
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towr
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Re: Integer Polynomial  
« Reply #2 on: Aug 10th, 2006, 3:23pm »
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I have the feeling there's something more missing from the question.
Because [sqrt]2/pi2 isn't rational, which is sufficient cause to say the left side of the equation can never be an integer, let alone 0.
« Last Edit: Aug 10th, 2006, 3:23pm by towr » IP Logged

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Re: Integer Polynomial  
« Reply #3 on: Aug 10th, 2006, 4:57pm »
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What you are saying makes sense but that is how I got it.
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Michael Dagg
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Re: Integer Polynomial  
« Reply #4 on: Aug 10th, 2006, 5:23pm »
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pi * pi = K^2 sqrt(2)/R + N/R    
 
says that  pi  would lie in the ring  Q( sqrt(2) )  and hence would satisfy  
a quadratic polynomial with integer coefficients.  Well, it doesn't.  
You could get away with merely knowing that  pi  is not constructible this  
way (i.e. lying in a chain of quadratic extensions of  Q), which is equivalent to  
the question of whether one can "square the circle"; but as far as I know  
there is no easy proof of that either.  
 
You could try to prove only the very weak claim that  pi  is not in this  
quadratic extension field  Q( sqrt(2) ). Since this claim is weaker than  
the other two, it might have an easier proof. But I don't know of any.  
 
I recall another problem in this forum much like this one and is in fact  
equivalent to it.
« Last Edit: Aug 10th, 2006, 5:38pm by Michael Dagg » IP Logged

Regards,
Michael Dagg
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