定义域满足
sin2x+1/2>0
sin2x > -1/2
画出sinx的图像易知在一个周期内,只有[7π/6,11π/6]是小于等于-1/2的.
∴ 2x∈[2kπ,2kπ+7π/6] ∪ [2kπ+11π/6,2kπ+2π]
∴ x∈[kπ,kπ+7π/12] ∪ [kπ+11π/12,kπ+π]
定义域满足
sin2x+1/2>0
sin2x > -1/2
画出sinx的图像易知在一个周期内,只有[7π/6,11π/6]是小于等于-1/2的.
∴ 2x∈[2kπ,2kπ+7π/6] ∪ [2kπ+11π/6,2kπ+2π]
∴ x∈[kπ,kπ+7π/12] ∪ [kπ+11π/12,kπ+π]