函数y=2sin(π/4-3x)的单调递减区间是 希望能给个正确的完整答案
问题描述:
函数y=2sin(π/4-3x)的单调递减区间是 希望能给个正确的完整答案
答
y = 2sin(π/4 - 3x) = -2sin(3x - π/4)
求减区间就是求sin(3x - π/4)的增区间
则3x - π/4 ∈(-π/2 + 2kπ,π/2 + 2kπ),k ∈Z
x ∈(-π/12 + 2kπ/3,π/4 + 2kπ/3),k ∈Z