三角函数概念是三角学的核心,三角函数概念的教学是整个三角学教学的重点和难点,这是由于:第一,三角函数概念贯穿于三角学,是三角函数图象和性质、三角运算(公式)、三角恒等变换和三角形边角关系(包括正、余弦定理)的学习的基础;第二,三角函数作为函数有其特殊性,学生进入高中后,本来就对集合论视角下函数定义存在理解障碍,甚至出现一些认识误区,三角函数与以前学习的指数函数、对数函数、幂函数相比研究的两个变量的对应关系更为隐 The concept of trigonometric functions is the core of trigonometry. The teaching of trigonometrical functions is the focus and difficulty of the whole trigonometry teaching. This is because: First, the concept of trigonometric functions runs through trigonometry, which is the image and nature of trigonometric functions. Triangular operations Formula), trigonometric identity transformation and triangular corner (including positive and cosine theorem) learning basis; second, trigonometric functions as a function of its particularity, students into high school, already on the set theory perspective function definition There are barriers to understanding, and even some misunderstandings. The correspondence between trigonometric functions and exponential functions, logarithmic functions and power functions studied in the past is more implicit