《中学生数学》2002年第12期(上)刊登的李光裕老师《例谈三角公式的巧用》一文,读后有所受益、有所启发.但该文第一部分例1的解法如果能将θ+15°作为一个整体去考虑来解决此题的话,不仅能体现三角公式的转化功能,而且方法更加简便,并且也不需要计算或记住75°和15°的三角函数值.更省去了后面的计算.解法如下: 例化简sin(θ+75°)+cos(θ+45°)-3~(1/3)cos(θ+15°). The article entitled “Interpretation of Trigonometric Formulas” by Teacher Li Guangyu published in “Secondary Student Maths”, Vol.12, 2002, has benefited and inspired. However, if the solution to the first part of this article is If θ+15° is considered as a whole to solve this problem, it not only can embody the conversion function of the triangular formula, but also the method is more convenient, and it does not need to calculate or remember the trigonometric function values ​​of 75° and 15°. The following calculations. The solution is as follows: Example Simplify sin(θ+75°)+cos(θ+45°)-3~(1/3)cos(θ+15°).