y=sin（x-6/π）cosx 最小值是,及对应的x值
问题描述：
y=sin（x-6/π）cosx 最小值是,及对应的x值
答
y=sin(x-π/6)cosx=(sinxcosπ/6-cosxsinπ/6)cosx=sinxcosxcosπ/6-cos²xsinπ/6=1/2sin2xcosπ/6-1/2(cos2x+1)sinπ/6=1/2(sin2xcosπ/6-cos2xsinπ/6)-1/2sinπ/6=1/2sin(2x-π/6)-1/4y最小=1/2×(-1)-1/4=-...