Question

设集合M={XI2sinx>=1,0

Answer 1

由2sinx≥1,得：

sinx≥1/2,

又∵ 0≤x≤π,

∴ π/6≤x≤5π/6

即：M=={x I π/6≤x≤5π/6 },

由cosx≤1/2,0≤x≤π,

∴ π/3≤x≤π

即：N={x I π/3≤x≤π },

∴ M∩N={x I π/3≤x≤5π/6},