1.函数y=sin(x+π/4)的单调递减区间是?2.函数y=2sin(2x+π/3)取最大值时x的集合?第一题是一道选择题( )[π/2,π] B,[0,π/4] C,[-π,0] D,[π/4,π/2]

1.函数y=sin(x+π/4)的单调递减区间是?2.函数y=2sin(2x+π/3)取最大值时x的集合?第一题是一道选择题( )[π/2,π] B,[0,π/4] C,[-π,0] D,[π/4,π/2]
1.函数y=sin(x+π/4)的单调递减区间是?2.函数y=2sin(2x+π/3)取最大值时x的集合?
第一题是一道选择题( )
[π/2,π] B,[0,π/4] C,[-π,0] D,[π/4,π/2]

1.函数y=sin(x+π/4)的单调递减区间是?2.函数y=2sin(2x+π/3)取最大值时x的集合?第一题是一道选择题( )[π/2,π] B,[0,π/4] C,[-π,0] D,[π/4,π/2]
1.(1).验A π/2≤x≤π ==>π/2+π/4≤x+π/4≤π+π/4 ==>3π/4≤x+π/4≤5π/4 (T)
(2).验D π/4≤x≤π/2==>π/4+π/4≤x+π/4≤π/2+π/4 ==>π/2≤x+π/4≤3π/4 (T)
A,D都是对的题目错了
2.当2x+π/3=π/2+2kπ 即 x=π/12+kπ 时,函数取最大值,取最大值的集合是
{x x=x=π/12+kπ }

选A。D错的。

恩~题错了~
令x+π/4∈[π/2±2kπ，3π/2±2kπ]，k∈Z
x∈[π/4±2kπ,5π/4±2kπ]
取最大值时，2x+π/3=π/2±2kπ k∈Z
x=π/6±2kπ

[2kπ-3π/4,2kπ+π/4]为递增。（2kπ+π/4,2kπ+5π/4)为递减
x=2kπ+π/12