判断三角形的形状,一般有两种思路:其一是化边为角,求出三个角之间的关系式,这有利于寻求角与角之间存在的内在联系;其二是化角为边,求出三条边之间的关系式.实施转化的主要策略是运用三角函数的关系式、向量和正(余)弦定理,下面分类例析三角形形状的判断. Judging the shape of a triangle, there are generally two ideas: one is to convert the edge to a corner, and to find the relationship between the three corners, which is conducive to seeking the inherent connection between the angle and the angle; the second is the angle of Edges, find the relationship between the three sides. The main strategy to implement the transformation is to use the trigonometric functions of the relational, vector and positive (co) string theorem, the following classification example analysis of the shape of the triangle.