抽象函数是指没有给出具体函数解析式,只给出了函数符号和一些体现函数特征的式子的一类函数。故而,抽象函数的性质隐而不见,抽象函数问题解决起来有一定的难度。但是,大量的抽象函数都是以基本函数为背景抽象而形成的,解题时,若能从研究抽象函数的“背景”入手,根据题设条件,通过类比、猜想,化抽象 The abstract function means that no specific function analytical formula is given, but only a function of the function symbol and some expressions that represent the characteristics of the function. Therefore, the nature of the abstract function is hidden, and it is difficult to solve the abstract function problem. However, a large number of abstract functions are formed by using basic functions as the background abstraction. When solving a problem, if you start from studying the background of abstract functions, according to the conditions of the questions, through analogy, conjecture, and abstraction