IMO 2008 Shortlist A5

Let a,b,c,d be positive real numbers such that abcd = 1 and a + b + c + d > a b + b c + c d + d a . Prove that a + b + c...

imomathematicsolympiadshortlistalgebra

IMO 2008 Shortlist A5

Category: Algebra

Problem

Let a,b,c,d be positive real numbers such that abcd = 1 and a + b + c + d > a b + b c + c d + d a . Prove that a + b + c + d < b a + c b + d c + a d .