在研究抽象函数时,有两类函数对称关系,形似而神异,容易混淆,做题时经常出错.下面给出这两组函数关系,并说明其应用. In the study of abstract functions, there are two types of functions with symmetrical relations. They are similar in shape and are ambiguous. They are confusing. They often make mistakes when they are asked. The following two sets of function relations are given and their applications are explained.