y=lg^sinx+根号下cos-1/2的定义域

y=lg sinx+√（cosx-1/2）则sinx＞0且cosx≥1/2,sinx＞0得 x∈（2kπ,2kπ+π）cosx≥1/2得x∈【2kπ-π/3,2kπ+π/3】取交集得x∈（2kπ,2kπ+π/3】即y=lg sinx+√（cosx-1/2）的定义域为{xI2kπ＜x＜2kπ+π/3,k...