IMO 2020 Shortlist A4

Let a,b,c,d be four real numbers such that a ě b ě c ě d ą 0 and abcd “ 1. Prove that pa 2b 3c 4dqaa bb cc dd ă 1. (Belg...

IMO 2020 Shortlist A4

Category: Algebra

Problem

Let a,b,c,d be four real numbers such that a ě b ě c ě d ą 0 and abcd “ 1. Prove that pa 2b 3c 4dqaa bb cc dd ă 1. (Belgium)