tanx>=-1,得：x为[kπ-π/4,kπ+π/2)
sinx>-1/2,得：x为(2kπ-π/6,2kπ+7π/6)
cosx>1/2,得：x为(2kπ-π/3,2kπ+π/3)
以上集合的交集即为解x的集合：
(2kπ-π/6,2kπ+π/3),k为任意整数