原式左边可变为cosπ/6×sinx+sinπ/6×cosx=sin（x+π/6）证毕2）sin（α+β）+ sin(α-β) =sina*cosβ+cosa*sinβ+sina*cosβ-cosa*sinβ=2sinαcosβ3）sin[（5π/6）-α]+sin[ （5π/6）+α] =sin（5π/6）*cos...