设函数f(x)=2sin (x-π⼀3)cosx,①求f(x)的最小正周期?②讨论 f(x)在[0,π⼀2]上单调性

2025-06-22 14:20:28
推荐回答(2个)
回答1:

(1)f(x)=2sin(x-π/3)cosx=sinxcosx-√3cos^2x=1/2sin2x-√3/2(1+cos2x)
=sin(2x-π/3)-√3/2
∴f(x)周期为T=2π/2=π。

(2) f(x)单调增区间:2kπ-π/2<=2x-π/3<=2kπ+π/2==>kπ-π/12<=x<=kπ+5π/12
∴f(x)在[0,5π/12]上单调递增,在[5π/12,π/2]上单调递减。

回答2:

只有外星人才看得懂