sinA+sinB=2sin(A+B)/2 *cos(A-B)/2cos2a=2cosa*cosa-1f(x)=2*sin2x*cos(π/6)+1+cos2x =sin2x+cos2x =√2*[sin2x*cos(π/4)+cos2x*sin(π/4)] =√2*sin(2x+π/4)最小值-√2最小正周期π