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在三角函数给角求值的问题中,为了达到求值的目的,必然要对给出的角进行分析,寻找它们的关系,并作出角的变换,使角度种类减少,或者三角函数可以“相消”或“相约”,或者在变换中产生特殊角从而直接得出三角函数的值.下面是给角求值思路的学习小结. 一、化为相同角 思路将不同的角化为同一角. 例1 计算: 略解都化为10°角,原式=1. 二、利用余补角 思路利用互余、互补的关系减少角度种类,进而相约.
In the problem of trigonometric evaluation of the angle, in order to achieve the purpose of evaluation, it is necessary to analyze the given angle, find the relationship between them, and make the transformation of the angle, so that the angle type is reduced, or the trigonometric function can be Cancel “or”, or generate special angles in the transformation to get the value of the trigonometric function directly. The following is the learning summary of the idea of the evaluation of the angle. First, to the same angle of thinking will be different angles into the same angle. Example 1 Calculation: Slightly solve all 10 degrees, the original formula = 1. Second, the use of complementary angle ideas to use mutual and complementary relationship to reduce the type of angle, and then similar.