cosx≥-1/2 x的范围怎么算?

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cosx≥-1/2x的范围怎么算?cosx≥-1/2x的范围怎么算?cosx≥-1/2x的范围怎么算?cosx≥-1/2=cos(-2π/3)=cos(2π/3)因为cosx在[2kπ,2kπ+π]上

cosx≥-1/2 x的范围怎么算?
cosx≥-1/2 x的范围怎么算?

cosx≥-1/2 x的范围怎么算?
cosx≥-1/2 = cos(-2π/3)=cos(2π/3)
因为cosx在[2kπ,2kπ+π]上递减,在[2kπ+π,2(k+1)π]上为递增函数,借助图像可得
2kπ-2π/3≤x ≤2kπ +2π/3.