二次函数是中学代数的基本内容,作为简明的幂函数(如 y=x~2),用它来引入、探究函数的单调性、奇偶性与最值问题自然亲切。而二次函数在闭区间上的最值问题件随着区间的确定或变化,除变量 x 与 y 之外、在系数中增添参变数的结构更新等,又成为高中会考或高考的热点知识。本文结合这类题的几种常见形式,释析其解法特点、 The quadratic function is the basic content of the middle school algebra, as a concise power function (such as y=x~2), it is natural to use it to introduce, explore the monotony of the function, parity and the most value problems. However, the value of the quadratic function in the closed interval is determined or changed along with the interval. In addition to the variables x and y, the structure updating of the parameter is added in the coefficient, and it becomes the hot knowledge of the high school entrance examination or college entrance examination. This article combines several common forms of this type of problem and explains the characteristics of its solution.