在一次视导中,课上我发现这样一个现象:教学内容是高一数学两角和与差的余弦公式,老师直接给出两角和与差的余弦公式,帮助学生观察分析公式结构,特别强调了等号两端函数的名称、符号特点,并留出时间让学生记忆.随后讲解例题,训练学生使用公式,公式正用、逆用、灵活运用都有涉及.而临近下课的课堂检测反馈表明,学生应用公式解题正确率很高. In a guide, I found during class that the teaching content is a high-math corner and a poor cosine formula. The teacher gives the cosine formula of the two corners and the difference directly to help students observe and analyze the structure of the formula, especially Emphasize the name of the function at both ends of the equal sign, symbolic features, and set aside time for students to remember. Then explain the examples, training students to use formulas, formulas are used, reverse, flexible use are involved. Show that students apply the formula to solve the problem is correct.