二次函数是最简单的非线性函数之一 ,自身性质活跃 ,同时经常作为其他函数的载体 .二次函数在某一区间上的最值问题 ,是初中二次函数内容的继续和发展 ,随着区间的确定或变化 ,以及在系数中增添参变数 ,使其又成为高考数学中的热点 .1　定二次函数在定区间上的最值二次函数是给 The quadratic function is one of the simplest non-linear functions. It is active in nature and often serves as a carrier for other functions. The problem of the maximum value of a quadratic function in an interval is the continuation and development of the content of the quadratic function in junior high school. With the determination or change of the interval, and the addition of parameter variables in the coefficient, it becomes a hot spot in the college entrance examination mathematics.1 The quadratic function of the quadratic function given in the interval is given