三角函数在复习时要熟练掌握三角变换的所有公式,理解每个公式的意义,应用特点,常规使用方法等;熟悉三角变换常用的方法——化弦法,降幂法,角的变换法等;并能应用这些方法进行三角函数式的求值、化简、证明;掌握三角变换公式在三角形中应用的特点,并能结合三角形的公式解决一些实际问题。同时,熟练掌握正弦函数、余弦函数、正切函数、余切函数的性质,形状、特点, Triangular function in the review should be proficient in all the formulas triangular transformation, understand the meaning of each formula, application characteristics, the use of conventional methods; familiar with the commonly used method of triangular transformation - the string method, the power law, the angle transformation method ; And can apply these methods to evaluate, simplify and prove the trigonometric functions; grasp the characteristics of the triangular transformation formula applied in the triangle and can solve some practical problems by combining the formula of the triangle. At the same time, master the sine function, cosine function, tangent function, the nature of the cotangent function, shape, characteristics,