A.y=sin(x/2+π/6)条件1不满足
B.y=cos(2x+π/3)x=pi/6的时候,2x+pi/3=2pi/3 ; y= -0.844444。条件2不满足
C和D是一样的
C.y=sin(2x+π/6)
D.y=cos(2x-π/3)