对称轴的梯度=0所以dy/dx = 0y = (1/2) sin (x - π/3)dy/dx = (1/2) cos (x - π/3)当 dy/dx = 00 = (1/2) cos (x - π/3)cos (x - π/3) = 0x - π/3 = π/2x = 5π/6对称轴,x = 5π/6