This topic mainly investigates the monotonicity of composite functions. First of all, you should be able to tell that this is a composite function. Secondly, you should have the concept of setting two functions, and then discuss the monotonicity of the two functions respectively (pay attention to the value range of the two functions themselves). Finally, you should know the principle of monotonicity of composite functions: the same increase but different decrease. The following two examples are my answers based on the above analysis process, hoping to help you.