已知函数fx =cos^2ωx+√3sinωxcosωx(ω>0)的最小正周期是π(1)求f(2/3π)的值⑵求函数f(x)(x∈(0,π))的单调区间

问题描述:

已知函数fx =cos^2ωx+√3sinωxcosωx(ω>0)的最小正周期是π(1)求f(2/3π)的值⑵求函数f(x)(x∈(0,π))的单调区间

f(x)=(1+cos2ωx)/2+√3sin2ωx
=sin(2ωx+π/6)+1/2
T=2π/(2ω)=π,ω=1,f(x)=sin(2x+π/6)+1/2
(1)f(2π/3)=sin(4π/3+π/6)+1/2=-1/2
(2)2x+π/6∈[2kπ-π/2,2kπ+π/2],k∈Z
解得x∈[kπ-π/3,kπ+π/6],k∈Z时单调递增,增区间为(0,π/6]和[2π/3,π)
减区间为[π/6,2π/3]