MathDB
There exist A, B, C such that lengths AB and AC are close

Source: Chinese TST 2007 2nd quiz P3

January 3, 2009
inequalitiescombinatorial geometryanalytic geometrygeometry

Problem Statement

Assume there are n3 n\ge3 points in the plane, Prove that there exist three points A,B,C A,B,C satisfying 1\le\frac{AB}{AC}\le\frac{n\plus{}1}{n\minus{}1}.