perplexus.info :: Just Math : Quadrilateral Sine Inequality

Quadrilateral Sine Inequality (Posted on 2008-08-05)

Let A,B,C and D be angles in a quadrilateral. Prove that:

√(CSinASinB)+√(ASinCSinD)+√(D|CosACosB|)+√(B|CosCCosD|) ≤ 2√(pi)

No Solution Yet Submitted by Jonathan Lindgren

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re: Solution

| Comment 2 of 3 |

(In reply to Solution by Praneeth)

You say:

You forgot to consider the case where the largest angle is
greater than 180.

I say: the largest angle is N E V E R
greater than 180.

Posted by Ady TZIDON on 2008-08-06 08:06:51

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