函数是高中数学的重要内容之一,它与数列、不等式等知识有着千丝万缕的联系,因此它贯穿于整个高中数学的始终。定义域作为构成函数的三要素之一,当然在研究函数性质时不可或缺。事实上,定义域是函数的几个性质中最基本的性质。因为在研究函数的其他性质(比如:函数的值域、单调性、奇偶性、对称性等)时都离不开它,而且有时借助函数的定义域可以为相关问题求解寻求更为简捷的途径。总之,函数的性质因为有了定义域而更富内涵,函数因它而熠熠生辉,在历届高考中 Function is an important part of high school mathematics. It is inextricably linked with knowledge of numbers and inequalities, so it runs through mathematics in high school. Defining a domain as one of the three elements that make up a function is, of course, indispensable when studying the nature of a function. In fact, a domain is the most basic of several properties of a function. Because it is inseparable from the study of other properties of the function (such as: the range of the function, monotonicity, parity, symmetry, etc.), and sometimes with the help of the domain of the function can solve the problem to find a more simple and easy way . In short, the nature of the function because of the definition of the domain and more content, the function shines because of it, in previous college entrance examination