y=2cos(π/3-1/2)单调减区间

题目

y=2cos(π/3-1/2)单调减区间
y=2cos(π/3-1/2x)单调减区间

答案

y=2cos(π/3-1/2x)
=2cos(x/2-π/3)
y=cosx单调减区间为 [2kπ,2kπ+π]
所以
2kπ