三角变换的特点是公式多,方法灵活,不容易掌握,所以在学习三角变换的时候必须总结一定的技巧和方法。基本思路可归纳为:一看角(角要尽量同角),二看函数种类(尽量化成同名函数或者是切割化弦),三看三角变换式子的特点(高次降幂,无理化为有理等等)。 Triangular transformation is characterized by multiple formulas, flexible methods, not easy to grasp, so learn triangle transformation must summarize certain skills and methods. The basic idea can be summarized as: a look at the corner (angle to try to be the same angle), second look at the type of function (as much as possible into the same name function or cut string), three look at the triangle transform the characteristics of Rational, etc.).