条件三角等式的证明在三角习题中是比较多见的,不少学生对这类题目感到棘手,其主要原因在于对这类题目的解题规律还没有很好地掌握。在教学中,宜从实际出发,指导学生运用对立统一的观点探求证明。首先要通过对比、分析寻找突破口,而突破口往往就是题中最显眼的差异:求证式与已知式的差异,求证式左右两端的差异,等等。差异就是矛盾,找出了差异,解决问题就是求得矛盾各方面的统一:求证式与已知式的统一,求证式左端与右端的统一。三角证明题中的差异主要表现在以下 The proving of conditional trigonometric equation is more common in trigonometry exercises. Many students find it difficult to deal with such problems. The main reason is that the rules of solving such problems are not well understood. In teaching, it is appropriate to proceed from the reality and guide the students to seek proof by using the view of unity of opposites. First of all, through contrast, analysis to find a breakthrough, and breakthrough often is the title of the most conspicuous difference: proof and known difference, proof of difference between the left and right, and so on. Differences are contradictions, to find out the differences, to solve the problem is to seek unity of all aspects of the contradiction: the unity of proof and known, proof of unity of the left and right. The difference in the proof of the triangle is mainly manifested in the following