文 [1]较系统地介绍了二次函数在闭区间上的最值问题的各种基本题型的求解方法 ,读后获益匪浅 .近年来的高考或竞赛重视能力立意 ,常在知识网络的交汇点上设计试题 .二次函数与二次方程、二次不等式和二次曲线等的交汇自然贴切 ,一脉相承 ,试题常以二次方程、二次不等式和二次 The paper [1] systematically introduced the solving methods of various basic problem types of the maximum value problem of the quadratic function in the closed interval, and benefited from the reading. In recent years, the college entrance examination or competition pays attention to the ability and intention, often in knowledge. The test points at the intersection of the network. The intersection of the quadratic function with the quadratic equation, the quadratic inequality and the quadratic curve, etc., is naturally appropriate, and they all come together in one continuous line. The test questions often use quadratic equations, quadratic inequalities, and quadratic tests.