1.sin(x-π/12)cos(x-π/12)=1/2 sin(2x-π/6)so T=2π/2=π2x-π/6=kπx=kπ/2+π/12所以最小正周期为π对城中心为（kπ/2,π/12）k∈Z2.cos2x=1-2sin²x1-cos2x=2sin²x根号下(1-cos2x)/cosx=√2sinx/cosx...