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+

π
3
)cos(
π
6
-x)的最大值及最小正周期分别为(  )
A.
1
2
π,2π
B.
1
2
,π
C. 1,π
D. 1,2π

由题意得,y=sin(x+

π
3
)cos(
π
6
-x)
=sin(x+
π
3
)cos[
π
2
-(x+
π
3
)]
=sin(x+
π
3
)
•sin(x+
π
3
)

=sin2(x+
π
3
)

=
1
2
1
2
cos(2x+
3
)

则函数的周期T=
|ω|
=π,函数的最大值是
1
2
1
2
×(−1)
=1,
故选:C.