(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Let ABCD be a convex cyclic quadrilateral. Prove that

[tex]|AB-CD|+|AD-BC| \geq 2|AC-BD|[/tex]

2. Relevant equations

3. The attempt at a solution

First, isn't a cyclic quadrilateral always convex?

http://en.wikipedia.org/wiki/Cyclic_quadrilateral

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# Homework Help: Putnam and Beyond prob 117

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