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急急急急正余弦函数的性质

来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/05/21 17:32:38

第十小题请老师详解
解题思路: 三角函数
解题过程:
10.解:y=3sin(π/6-3x)=-3sin(3x-π/6),x∈[-π/2,π/2]的单调递增区间即y=3sin(3x-π/6)x∈[-π/2,π/2]的单调递减区间,由2kπ+π/2<=3x-π/6<=2kπ+3π/2,2kπ/3+2π/9<=x<=2kπ/3+5π/9,
k=-1,0时-4π/9<=x<=-π/9,2π/9<=x<=5π/9,结合x∈[-π/2,π/2]得
y=3sin(π/6-3x)x∈[-π/2,π/2]的单调递增区间为: [-4π/9,-π/9],[2π/9,π/2]
最终答案:略