2. (2022春•南阳期末)函数y=sinx+12−cosxy=\sqrt{\sin x}+\sqrt{\frac{1}{2}-\cos x}y=sinx+21−cosx的定义域是___[2kπ+π3,2kπ+π](k∈Z)[2k\pi +\frac{\pi }{3},2k\pi +\pi ](k\in Z)[2kπ+3π,2kπ+π](k∈Z)___.