求函数y=2sin(3x+4分之π)的单调递减区间.
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求函数y=2sin(3x+4分之π)的单调递减区间.
求函数y=2sin(3x+4分之π)的单调递减区间.
求函数y=2sin(3x+4分之π)的单调递减区间.
π/2+2kπ
π/2+2kπ<3x+π/4<3π/2+2kπ
π/4+2kπ<3x<5π/4+2kπ
π/12+2kπ/3
祝你开心!希望能帮到你,如果不懂,请追问,祝学习进步!O(∩_∩)O换元法有没有?令3x+π/4=t,y=2sint的递减区间是:π/2+2kπ
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π/2+2kπ<3x+π/4<3π/2+2kπ
π/4+2kπ<3x<5π/4+2kπ
π/12+2kπ/3
祝你开心!希望能帮到你,如果不懂,请追问,祝学习进步!O(∩_∩)O
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y=2sin(3x+π/4)
因为,对于y=sina, 在[2kπ-π/2, 2kπ+π/2]上为增函数
所以令 2kπ-π/2 <=3x+π/4 =<2kπ+π/2
解得 2kπ-3π/4 <=3x =<2kπ+π/4
2kπ/3- π/4 <=3x =<2kπ/3+π/12
所以增区间为 [2kπ/3- π/...
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y=2sin(3x+π/4)
因为,对于y=sina, 在[2kπ-π/2, 2kπ+π/2]上为增函数
所以令 2kπ-π/2 <=3x+π/4 =<2kπ+π/2
解得 2kπ-3π/4 <=3x =<2kπ+π/4
2kπ/3- π/4 <=3x =<2kπ/3+π/12
所以增区间为 [2kπ/3- π/4 , 2kπ/3+π/12]
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