MathDB
JBMO 2018, P3

Source: JBMO 2018

June 21, 2018

Problem Statement

Let k>1k>1 be a positive integer and n>2018n>2018 an odd positive integer. The non-zero rational numbers x1,x2,,xnx_1,x_2,\ldots,x_n are not all equal and: x1+kx2=x2+kx3=x3+kx4==xn1+kxn=xn+kx1x_1+\frac{k}{x_2}=x_2+\frac{k}{x_3}=x_3+\frac{k}{x_4}=\ldots=x_{n-1}+\frac{k}{x_n}=x_n+\frac{k}{x_1} Find the minimum value of kk, such that the above relations hold.