MathDB
Minimum value of cosine sum (easy variant)

Source: Russian TST 2014, Day 10 P3 (Groups A & B)

January 8, 2024
algebratrigonometryminimum value

Problem Statement

Let x,y,zx,y,z be real numbers. Find the minimum value of the sum \begin{align*}|\cos(x)|+|\cos(y)|+|\cos(z)|+|\cos(x-y)|+|\cos(y-z)|+|\cos(z-x)|.\end{align*}