函数f(x)=cos(2x-π⼀6)在[0,π]的单调增区间

2025-05-17 11:53:36
推荐回答(1个)
回答1:

  1. f(x)=cos(2x-π/6)

    将2x-π/6建成整体:单调递增区间2x-π/6∈(2kπ-π,2kπ)→x∈(kπ-5π/12,kπ+π/12)

    对照给定区间:单调递增区间x∈(7π/12,π]

  2. f(x)=½sin2x+√3/2cos2x=sin(2x+π/6)

    最大值2x+π/6=π/2→f(π/6)=1

    最小值f(π/2)=sin(π+π/6)=-sin(π/6)=-½

  3. f(x)≥√2/2→2kπ+¼π≤x≤2kπ+¾π