三角不等式问题主要包括两个方面 :三角不等式与三角最值 .它是与三角恒等式密切相关的 ,运用三角公式对式子进行恒等变形是处理三角不等式问题的重要方法 ,有时三角最值问题就是基于三角公式而得到解决的 .1　三角不等式三角不等式首先是不等式 ,因此 ,有关不等式的性质和证明 The problem of triangular inequality mainly includes two aspects: triangle inequality and triangle maximum value. It is closely related to triangular identity. Using triangle formulae to perform isomorphic deformation of equations is an important method to deal with triangular inequality problems. Sometimes the triangular minimum value problem is The triangular inequality triangle inequality solved based on the trigonometric formula is inequality first, and therefore, the property and proof of the inequality