a+b+c+d=2 and ab+bc+cd+da+ac+bd = 0, find min, max of abcd
Source: Balkan BMO Shortlist 2016 A5
July 30, 2019
algebrasystem of equationsinequalitiesminimummaximumIMO Shortlist
Problem Statement
Let and be real numbers such that and .
Find the minimum value and the maximum value of the product .