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三角函数一章中,角的公式比较多,解决问题时同学们有时感到比较困难,无从下手.在此谈几种有关三角函数中“角”问题的处理方法,希望对同学们的学习有所帮助.1.将非特殊角转化为特殊角例:求sin15°sin30°sin75°的值.分析:题中有一个值可求,另两个均为非特殊角的三角函数值,而sin15°可以转化为sin(45°-30°),同时可以把sin75°转化为sin(45°+30°),再利用两角和公式展开求解
In the chapter of trigonometric functions, there are many formulas for angles. When solving problems, students sometimes find it difficult to start. There are several ways to deal with the “corner” problem in trigonometric functions. I hope to learn from the students. Learning to help. 1. Turn non-special angles into special cases: find the value of sin15°sin30°sinin75°. Analysis: There is a value that can be found in the question, and the other two are trigonometric values that are not special angles. While sin15° can be converted to sin(45°-30°), and sin75° can be converted to sin(45°+30°), and then solved using two angles and formulas.