y=2sin(-2x+π/3) 和y=3cos(2/3x+π/4)单调区间
问题描述：
y=2sin(-2x+π/3) 和y=3cos(2/3x+π/4)单调区间
答
-2x+π/3∈【2kπ-π/2,2kπ+π/2】
即x∈【kπ-π/12,kπ+5π/12】
y=2sin(-2x+π/3)单调递增
-2x+π/3∈【2kπ+π/2,2kπ+3π/2】
即x∈【kπ-7π/12,kπ-π/12】
y=2sin(-2x+π/3)单调递减
同理
2/3x+π/4∈【2kπ-π,2kπ】
即x∈【kπ-15π/8,kπ+3π/8】
y=3cos(2/3x+π/4)单调递增
2/3x+π/4∈【2kπ,2kπ+π】
即x∈【kπ-3π/8,kπ+9π/8】
y=3cos(2/3x+π/4)单调递减
答
若曦涟漪：注：楼上回答可能计算有误!y＝2sin(－2x＋π/3)单调递增区间：由：－π/2＋2kπ≤－2x＋π/3≤π/2＋2kπ得：－π/12－kπ≤x≤5/12π－kπ,k∈Z即：[－π/12－kπ,5/12π－kπ]单调递减区间：由：π/2＋2...