变化成题推陈出新,本是各类数学竞赛、高考命题者的命题途径,现已成为广大中学数学教师常用的教学方法。本文将沿用此方法探讨以下三角不等式: Changes into new topics, this is the proposition of various types of mathematical contests, college entrance examination propositions, has now become a common school mathematics teachers in teaching methods. This article will use this method to explore the following triangle inequalities: