关于函数f(x)=4sin(2x+ x 3 )(x∈R),有下列命题:?①由f(x 1 )=f(x 2 )=0可得x 1

2025-06-26 05:35:57
推荐回答(1个)
回答1:

①函数f(x)=4sin (2x+
π
3
)
的最小正周期T=π,
由相邻两个零点的横坐标间的距离是
T
2
=
π
2
知①错.
②f(x)=4sin(2x+
π
3
)=4cos(
π
2
-2x-
π
3
)=4cos(2x+
π
3
-
π
2
)=4cos(2x-
π
6

③f(x)=4sin(2x+
π
3
)的对称点满足(x,0)
2x+
π
3
=kπ,x=( k-
π
3
π
2
   k∈Z
(-
π
6
,0)满足条件
④f(x)=4sin(2x+
π
3
)的对称直线满足
2x+
π
3
=(k+
1
2
)π;x=(k+
1
6
π
2

x=-
π
6
不满足
故答案为:②③