抽象函数是一种重要的数学概念。我们把没有给出具体解析式,其一般形式为y=(fx),且无法用数字和字母的函数称为抽象函数。由于抽象函数的问题通常将函数的定义域、值域、单调性、奇偶性、周期性和图像集于一身。这类问题考查学生对数学符号语言的理解和接受能力、对一般和特殊关系的认识以及数学的综合能力。一、抽象函数的定义域例1已知函数(fx)的定义域为[1,3], Abstract function is an important mathematical concept. We did not give a specific analytical form, the general form of y = (fx), and can not use numbers and letters of the function is called an abstract function. Due to the problem of abstract functions, the function’s domain, value range, monotonicity, parity, periodicity and image are usually combined into one. Such questions examine students’ understanding and acceptance of mathematical notation languages, their knowledge of general and specific relationships, and the comprehensive ability of mathematics. First, the abstract function of the domain Example 1 Known function (fx) domain is [1,3],