函数y=sin(x+π3)cos(π6-x)的最大值及最小正周期分别为( ) A.12π,2π B.12,π C.1,π D.1,2π
问题描述:
函数y=sin(x+
)cos(π 3
-x)的最大值及最小正周期分别为( )π 6
A.
π,2π1 2
B.
,π1 2
C. 1,π
D. 1,2π
答
由题意得,y=sin(x+
)cos(π 3
-x)π 6
=sin(x+
)cos[π 3
-(x+π 2
)]π 3
=sin(x+
)•sin(x+π 3
)π 3
=sin2(x+
)π 3
=
−1 2
cos(2x+1 2
),2π 3
则函数的周期T=
=π,函数的最大值是2π |ω|
−1 2
×(−1)=1,1 2
故选:C.