“按某种顺序”是什么顺序?在高考题或模拟题中,新出现一种“顺序自定”型问题,即所给的几个数按某种顺序赋值或构成一个等量关系,而这个“某种顺序”需要考生自己分析、建立,实际上多数情况下需要充分地分类讨论.例1(2015年上海文科卷第13题)已知平面向量a,b,c满足a⊥b,且{|a|,|b|,|c|}={1,2,3},则|a+b+c|的最大值 “In a certain order ” What order? In college entrance examination questions or simulation questions, the emergence of a “self-ordering ” type of problem, that is given a few numbers in some order assignment or constitute a In fact, most of the cases need to be fully classified and discussed.Example 1 (Shanghai literary volume in 2015, the first 13 questions) known plane vector a, b, c satisfies a ⊥ b, and {| a |, | b |, | c |} = {1,2,3}, the maximum value of | a + b + c |