max S=x_1(1-x_2)+x_2(1-x_3)+x_3(1-x_4)+\cdots +x_{99}(1-x_{100})+x_ {100}(1-x_1)
Source: Argentina 1997 OMA L3 p3
May 13, 2024
algebraSuminequalities
Problem Statement
Let x1,x2,x3,…,x100 be one hundred real numbers greater than or equal to 0 and less than or equal to 1. Find the maximum possible value of the sumS=x1(1−x2)+x2(1−x3)+x3(1−x4)+⋯+x99(1−x100)+x100(1−x1).