在中学数学教材中已介绍了基本初等函数的单调性,对于复合函数的单调性的判定却未讲。然而有些数学问题又涉及到复合函数单调性的判定,如近年高考数学试题中就有这类问题。因此寻求判定复合函数单调性的方法是有必要的,特别是简单易行的初等方法更利于中学数学教学。 The monotonicity of elementary elementary functions has been introduced in middle school mathematics textbooks, but the monotonicity of compound functions has not been discussed. However, some mathematical problems involve the determination of the monotonicity of compound functions. For example, in the recent college entrance examination mathematics test questions, there are such problems. Therefore, it is necessary to seek to determine the monotonicity of the compound function, especially the simple and easy elementary method is more conducive to middle school mathematics teaching.