# 2006 IMO Problems/Problem 3

## Problem

Determine the least real number such that the inequality $\left|ab\left(a^{2}-b^{2}\right)+bc\left(b^{2}-c^{2}\right)+ca\left(c^{2}-a^{2}\right)|\leq M\left(a^{2}+b^{2}+c^{2}\right)^{2}$ (Error compiling LaTeX. ! Missing \right. inserted.) holds for all real numbers and

## Solution

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