现行教材中出现的某些求三角函数(或复合函数)的值域或定义域的问题需要求出三角不等式的解,而教材中对于解三角不等式无定法可循,我们在教学中对于利用单位圆或三角函数的图象来解三角不等式作了一些尝试,现举几例加以简要说明,以抛砖引玉。例1 解不等式2~(1/2)+2cosx≥0。解原不等式等价于不等式 In the current teaching materials, some questions about the range or definition domain of the trigonometric function (or compound function) need to be solved for the solution of the triangle inequality. In the textbook, there is no fixed method for solving the triangular inequality. We use the unit in teaching. Some attempts have been made to solve the triangle inequality by using the image of a circle or a trigonometric function. Here are a few examples to give a brief explanation and to give an introduction. Example 1 Solution Inequality 2~(1/2)+2cosx≥0. Solution of original inequality equivalent to inequality