有些平面几何证明题若采用三角法证明往往比较简单。这是因为几问题的综合证法解法灵活，构思较难，有时还需巧添辅助线。而三角法可以定量地表示三角形中边角之间的关系，能够在不添或少添辅助线的情况下，把几何定性推理证明转化为三角关系式，从而化难为易，达到证题的目的 Some plane geometrical proofs are usually simpler if they are proved by trigonometry. This is because the comprehensive evidence method of several issues is flexible and difficult to conceptualize, and sometimes it is necessary to add an auxiliary line. The trigonometric method can quantitatively represent the relationship between the corners of a triangle, and can convert the geometrical qualitative reasoning into a trigonometric relation without adding or subtracting the auxiliary line, thus making it difficult to achieve the purpose of the test.