作业帮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]
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![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]](/uploads/image/z/7651002-66-2.jpg?t=1.%E5%87%BD%E6%95%B0y%3Dsin%28x%2B%CF%80%2F4%29%E7%9A%84%E5%8D%95%E8%B0%83%E9%80%92%E5%87%8F%E5%8C%BA%E9%97%B4%E6%98%AF%3F2.%E5%87%BD%E6%95%B0y%3D2sin%282x%2B%CF%80%2F3%29%E5%8F%96%E6%9C%80%E5%A4%A7%E5%80%BC%E6%97%B6x%E7%9A%84%E9%9B%86%E5%90%88%3F%E7%AC%AC%E4%B8%80%E9%A2%98%E6%98%AF%E4%B8%80%E9%81%93%E9%80%89%E6%8B%A9%E9%A2%98%28+%29%5B%CF%80%2F2%2C%CF%80%5D+B%2C%5B0%2C%CF%80%2F4%5D+C%2C%5B-%CF%80%2C0%5D+D%2C%5B%CF%80%2F4%2C%CF%80%2F2%5D)
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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