“函数单调性”是学生进入高中后较早接触到的一个完全形式化的抽象定义,对仍处于经验型逻辑思维发展阶段的高一学生来讲,有较大的学习难度.主要表现在:形式化的定义如何得到,即如何由“y随着x的增大而增大(或减小)”得到“对任意x1x2,均有f(x1)f(x2)(或f(x1)f(x2))”;利用? “Monotoneity of functions” is a completely formalized abstract definition that students came into contact with earlier in high school. It is more difficult for freshmen who are still in the stage of development of empirical logical thinking, which is mainly manifested in the following aspects: How a formalized definition is obtained, ie, how to get “y” as “increasing” (or decreasing) with increasing x, has f (x1) f (x2) for any x1x2 (or f (x2)) "; use?