函数y=cos(π/6)cos(2x)+sin(π/6)sin(2x)的单调递减区间是?cos(π/6-2x)与cos(2x-π/6)单调递减区间一样吗?

来源:学生作业帮助网 编辑:作业帮 时间:2024/05/03 03:35:21
函数y=cos(π/6)cos(2x)+sin(π/6)sin(2x)的单调递减区间是?cos(π/6-2x)与cos(2x-π/6)单调递减区间一样吗?

函数y=cos(π/6)cos(2x)+sin(π/6)sin(2x)的单调递减区间是?cos(π/6-2x)与cos(2x-π/6)单调递减区间一样吗?
函数y=cos(π/6)cos(2x)+sin(π/6)sin(2x)的单调递减区间是?
cos(π/6-2x)与cos(2x-π/6)单调递减区间一样吗?

函数y=cos(π/6)cos(2x)+sin(π/6)sin(2x)的单调递减区间是?cos(π/6-2x)与cos(2x-π/6)单调递减区间一样吗?
y=cos(π/6)cos(2x)+sin(π/6)sin(2x) =cos(2x-π/6)
令2kπ

y=cos(π/6)cos(2x)+sin(π/6)sin(2x)=cos(2x-π/6)=sin(2x+π/3)
2x+π/3∈[2kπ+π/2,2kπ+3π/2] k∈Z
x∈[kπ+π/12,kπ+7π/12] k∈Z
单调递减区间[kπ+π/12,kπ+7π/12] k∈Z