三角函数是数学中非常基础的内容,学好它对于每一位学生来说都非常重要,教好它也是对一位教师的重大考验。三角函数的相关知识内容丰富,变化多样。笔者在教学实践中发现掌握一些主要的公式或者规律,对三角函数的学习非常有用。首先,是一个公式:sin2x+cos2x=1这个公式很多学生都很熟悉,大家可能会想,这太简单了吧?但是,这个公式为什么成立呢?很多学生都没有想过这个问题,或者想到也不深究。对于这个公式,我们可以从以下几个方 Trigonometry is a very basic part of mathematics. To learn it well is important to every student. To teach it is also a great test for a teacher. The related knowledge of trigonometric functions is rich in content and varied. The author found in teaching practice to master some of the major formulas or laws, the study of trigonometric functions is very useful. First of all, is a formula: sin2x + cos2x = 1 Many students are familiar with this formula, we may think, this is too simple, but why the formula was established? Many students have never thought of this problem, or think of Do not go deep into it. For this formula, we can from the following parties