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   Author  Topic: Sharp Lower Bound  (Read 704 times)
Michael Dagg
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Sharp Lower Bound  
« on: May 1st, 2009, 9:44am »
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Inspired from an other problem here:
 
Suppose that all the coefficients of
 
p(x) = x^n + a_{n-1} x^{n-1} + ... + a_1 x + 1
 
are positive and the  n  roots of  p  are real.
 
Determine a sharp lower bound for  p(2).
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Michael Dagg
Obob
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Re: Sharp Lower Bound  
« Reply #1 on: May 1st, 2009, 11:55am »
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3^n, satisfied by p(x) = (x+1)^n
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Aryabhatta
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Re: Sharp Lower Bound  
« Reply #2 on: May 1st, 2009, 3:05pm »
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I get the same result as Obob.
 
A thread which appeared earlier might be helpful:
 
http://www.ocf.berkeley.edu/~wwu/cgi-bin/yabb/YaBB.cgi?board=riddles_med ium;action=display;num=1179865908
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Obob
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Re: Sharp Lower Bound  
« Reply #3 on: May 1st, 2009, 3:15pm »
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Ha, I totally forgot about that one.
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Aryabhatta
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Re: Sharp Lower Bound  
« Reply #4 on: May 1st, 2009, 4:19pm »
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on May 1st, 2009, 3:15pm, Obob wrote:
Ha, I totally forgot about that one.

 
Not unreasonable, considering the fact that I almost forgot it too, and I started that thread!
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