MathDB
sum is over the consecutive square of the segments

Source: China TST 1986, problem 4

May 16, 2005
inductiongeometrygeometry unsolved

Problem Statement

Given a triangle ABCABC for which C=90C=90 degrees, prove that given nn points inside it, we can name them P1,P2,,PnP_1, P_2 , \ldots , P_n in some way such that: k=1n1(PKPk+1)2AB2\sum^{n-1}_{k=1} \left( P_K P_{k+1} \right)^2 \leq AB^2 (the sum is over the consecutive square of the segments from 11 up to n1n-1). Edited by orl.