函数是高中数学第一个比较抽象,难理解的概念之一。它描述了自然界中量的依存关系,通过刻画现实世界中量与量之间的数量关系,反映了一个量随着另一个量变化而变化之规律。函数的思想方法就是提取问题的数学本征,建立函数关系, Function is one of the more abstract and difficult-to-understand concepts of math in high school. It describes the amount of dependence in nature, and by characterizing the quantitative relationship between quantity and quantity in the real world, reflects the law that one quantity changes as another quantity changes. The function of the method is to extract the mathematical problem of the problem, the establishment of functional relationships,