“二次函数”这部分内容在整个初中数学中占有很重要的位置 ,特别是在近几年的中考试卷里 ,最后一道大题都是有关二次函数的题目。但这部分内容在教材中讲得简单 ,而在考试时所涉及到的知识多 ,变化大。学生较难掌握 ,因此这部分知识是失分最多的地方。那么如何突破既重要又困 The part of “quadratic function” plays a very important role in the mathematics of junior middle school. Especially in the middle school examination papers in recent years, the last topic is about the topic of quadratic function. However, this part of the content is simple in teaching materials, and the knowledge involved in the examination is numerous and changes greatly. Students are more difficult to master, so this part of the knowledge is the most misleading. So how to break through is both important and sleepy