Y by Adventure10, Mango247
Let
be the sum of the lengths of all the diagonals of a plane convex polygon with
vertices (where
). Let
be its perimeter. Prove that:
![\[ n-3<{2d\over p}<\Bigl[{n\over2}\Bigr]\cdot\Bigl[{n+1\over 2}\Bigr]-2,\]](//latex.artofproblemsolving.com/6/e/e/6eea62bf3ef064f376ac03e6201927938c600e9f.png)
where
denotes the greatest integer not exceeding
.




![\[ n-3<{2d\over p}<\Bigl[{n\over2}\Bigr]\cdot\Bigl[{n+1\over 2}\Bigr]-2,\]](http://latex.artofproblemsolving.com/6/e/e/6eea62bf3ef064f376ac03e6201927938c600e9f.png)
where
![$ [x]$](http://latex.artofproblemsolving.com/1/0/5/105f81f70e5e3f58e5cfff9e54072a0acdee0402.png)

Stay ahead of learning milestones! Enroll in a class over the summer!
Something appears to not have loaded correctly.