f（x）=2(sinxcosπ/6+cosxsinπ/6)-2cosx =2(根号3/2*sinx+1/2*cosx)-2cosx=根号3*sinx-cosx=2(cosπ/6sinx-sinπ/6cosx)=2sin(x-π/6),x∈[0,π/2].00所以2x-π/3∈(π/3,π/2)sin(2x-π/3)=24/25∴cos(2x-π/6)=c...