已知函数f(x)=sin(2x+π6)+sin(2x−π6)+2cos2x. (1)求f(x)的最大值及最小正周期; (2)求使f(x)≥2的x的取值范围.

问题描述:

已知函数f(x)=sin(2x+

π
6
)+sin(2x−
π
6
)+2cos2x.
(1)求f(x)的最大值及最小正周期;
(2)求使f(x)≥2的x的取值范围.

(1)∵f(x)=sin(2x+π6)+sin(2x−π6)+2cos2x=sin2xcosπ6+cos2xsinπ6+sin2xcosπ6−cos2xsinπ6+2cos2x+1=3sin2x+cos2x+1=2sin(2x+π6)+1.∴f(x)max=2+1=3.T=2π|ω|=2π2=π.(2)∵f(x)≥2,∴2sin(2...