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Regional Olympiad - FBH 2012 Grade 9 Problem 1

Source: Regional Olympiad - Federation of Bosnia and Herzegovina 2012

September 25, 2018
algebraidentityvalue

Problem Statement

Find all possible values of 1a(1b+1c+1b+c)+1b(1c+1a+1c+a)+1c(1a+1b+1a+b)1a+b+c(1a+1b+1c+1a+b+1b+c+1c+a)+1a2+1b2+1c2\frac{1}{a}\left(\frac{1}{b}+\frac{1}{c}+\frac{1}{b+c}\right)+\frac{1}{b}\left(\frac{1}{c}+\frac{1}{a}+\frac{1}{c+a}\right)+\frac{1}{c}\left(\frac{1}{a}+\frac{1}{b}+\frac{1}{a+b}\right)-\frac{1}{a+b+c}\left(\frac{1}{a}+\frac{1}{b}+\frac{1}{c}+\frac{1}{a+b}+\frac{1}{b+c}+\frac{1}{c+a}\right)+\frac{1}{a^2}+\frac{1}{b^2}+\frac{1}{c^2} where aa, bb and cc are positive real numbers such that ab+bc+ca=abcab+bc+ca=abc