IMO 2020 Shortlist A3

Suppose that a, b, c, d are positive real numbers satisfying pa cqpbdq “ ac bd. Find the smallest possible value of a b ...

IMO 2020 Shortlist A3

Category: Algebra

Problem

Suppose that a, b, c, d are positive real numbers satisfying pa cqpbdq “ ac bd. Find the smallest possible value of a b b c c d d a . (Israel)