判断两个角集之间的关系是初学三角函数的同学常易出错的问题 .下面通过实例 ,说明如何解此种题型 .1　列举法当两个角集中含有整数ｋ时 ,列举ｋ的几个特殊值 ,如ｋ取 0 ,± 1 ,± 2 ,… ,通过观察两个角集中的元素 ,就可以判断两个角集之间的关系 .例 1　若Ｍ ={ｘ|ｘ =ｋπ± Judging the relationship between the two angle sets is often an error-prone problem for beginners with trigonometric functions. The following examples illustrate how to solve this type of problem. 1 Enumeration method When two corner sets contain the integer k, enumerate the number of k Special values ​​such as k take 0, ±1, ±2,..., By observing the elements of two angle sets, we can determine the relationship between two angle sets. Example 1 If M = {x|x = kπ±