抽象函数是指没有给出函数的具体解析式,只给出了一些体现函数特征的式子的一类函数.由于抽象函数表现形式的抽象性,使得这类问题成为函数内容的难点之一,但是这类问题对于培养学生的创新精神和实践能力,增强用数学的意识,有着十分重要的作用,从而成为近年来高中各类考试命题的热点.有些抽象型函数问题,用常规方法往往难以奏效,或过程十分繁杂.若能利用赋值法求解,常会收到事半功倍之效.一、判断函数的奇偶性 Abstract function refers to a kind of function that does not give a concrete expression of a function but only gives some formulas that reflect the characteristic of a function.As a result of the abstraction of abstract function representation, However, such questions play an important role in cultivating students’ innovative spirit and practical ability and enhancing their awareness of mathematics, which has become a hot topic in all kinds of examination questions in high school in recent years. Some abstract function problems are often difficult to be performed by conventional methods , Or the process is very complicated.If you can use the assignment method to solve, often will get a multiplier effect. First, determine the function of parity