MathDB
find the maximum and minimum

Source: 2022 China Second Round A1 P1

October 30, 2022
maximum and minimuminequalities

Problem Statement

a,b,c,da,b,c,d are real numbers so that ab,cda\geq b,c\geq d,a+2b+3c+4d=1.|a|+2|b|+3|c|+4|d|=1. Let P=(ab)(bc)(cd)P=(a-b)(b-c)(c-d),find the maximum and minimum value of PP.