弧度制这一有难度的概念教学,关键是找准学生知识的生长点,抓住核心公式。在一次数学教研活动中,教研组让笔者开设公开课,指定课题是“弧度制”。笔者的心一下子就紧张了,这节课太难上了!其一,不易找到与弧度制理想的知识结合点和技能生长点;其二,弧度定义的出台有些突兀,不易做到自然顺畅;其三,与本节课有关的素材不够丰富;其四,不易找到与其相匹配的理想练习题。看到笔者的犹豫,笔者的“教练”著名特级教师 Radical system of the difficult concept of teaching, the key is to identify the growth point of student knowledge, grasp the core formula. In a mathematics teaching and research activities, teaching and research group let the author open class, the designated subject is “arc system ”. The author’s heart suddenly nervous, this class is too difficult! First, it is not easy to find the ideal combination of knowledge and curvature of the point and skills to grow point; Second, the introduction of radian definition of some abrupt, not easy to be natural and smooth ; Third, the material related to this lesson is not rich enough; Fourth, it is not easy to find the ideal exercise to match. See the author’s hesitation, the author’s “coach” famous super-teacher