limits of brocard angle

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Tahmid Hasan
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limits of brocard angle

Unread post by Tahmid Hasan » Mon May 30, 2011 11:40 pm

Prove that brocard angles can not be bigger than $30$ degrees.
if you don't know about brocard angles and points then here's 2 links:
en.wikipedia.org/wiki/Brocard_points
http://mathworld.wolfram.com/BrocardPoints.html
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*Mahi*
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Re: limits of brocard angle

Unread post by *Mahi* » Mon Jun 06, 2011 12:59 am

Hint:
Use Jensen's inequality-
For $x_i\in [0,\pi]$
$\sum \frac{sin x_i}{n}\leq {sin {\frac{\sum x_i}{n}}}$
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Tahmid Hasan
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Re: limits of brocard angle

Unread post by Tahmid Hasan » Mon Jun 06, 2011 10:06 am

hehe,i used Erdos-mordell inequality:
math.ust.hk/excalibur/v2_n4
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Re: limits of brocard angle

Unread post by *Mahi* » Mon Jun 06, 2011 12:21 pm

Yeah,that also works,but Jensen's inequality works in much more cases(I mentioned only a special case)
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