根据我个人的体会,在高一数学第三、四章教学中,应注意以下几个问题。一、三角函数式的积化和差与和差化积是三角函数式的重要恒等变形。旧课本在讲完三角函数的和差化积后,对积化和差一带而过,只在习题中出现。新课本则比较重视,不仅正式讲积化和差公式,而且突出为什么要学习积化和差:“在计算与化简的过程 According to my personal experience, in the third and fourth chapters of mathematics teaching, we should pay attention to the following questions. First, the product of trigonometric functions and the difference sum and difference products are the important constant deformations of the trigonometric function. After the old textbooks had covered the trigonometric functions and the differential products, they had passed over the product and the difference, and only appeared in the exercises. New textbooks are more important, not only formally speaking about product and difference formulas, but also highlight why we must learn to accumulate and poor: "The process of calculation and simplification