二次函数是最简单的非线性函数之一,以此为核心同与之紧密相联的二次方程及二次不等式并称三个“二次”.它们是中学数学的重要内容,具有丰富的内涵,同时也是研究包含二次曲线在内的许多数学问题的工具,而且对近代数学,乃至现代数学,影响深远,因而为历年来高考数学考试的一项重 The quadratic function is one of the simplest non-linear functions. It is the core and the quadratic equations and quadratic inequalities that are closely related to it. We call them three “secondarys.” They are an important part of middle school mathematics and are rich in The connotation is also a tool for studying many mathematical problems including the quadratic curve, and it has a far-reaching impact on modern mathematics and even modern mathematics. It is therefore a major factor in the mathematics test of the college entrance examination.