函数y=2sin(3x+π4)-1的单调递减区间为_.
问题描述:
函数y=2sin(3x+
)-1的单调递减区间为______. π 4
答
令2kπ+
≤3x+π 2
≤2kπ+π 4
,k∈z,求得 3π 2
+2kπ 3
≤x≤π 12
+2kπ 3
,7π 36
故函数的减区间为 [
+2kπ 3
,π 12
+2kπ 3
],k∈Z,7π 36
故答案为:[
+2kπ 3
,π 12
+2kπ 3
],k∈z.7π 36