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已知数列{an}是等比数列,Sn为其前n项和.(1)若S4,S10,S7成等差数列,证明a...
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已知数列{a
n}是等比数列,S
n为其前n项和.
(1)若S
4,S
10,S
7成等差数列,证明a
1,a
7,a
4也成等差数列;
(2)设
![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACgAAAAjCAYAAADmOUiuAAAAAXNSR0IArs4c6QAAAARnQU1BAACx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=
)
,
![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAC8AAAAjCAYAAAAE5VPXAAAAAXNSR0IArs4c6QAAAARnQU1BAACx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)
,b
n=λa
n-n
2,若数列{b
n}是单调递减数列,求实数λ的取值范围.
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已知an=![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAH8AAAA9CAYAAACELbZ0AAAAAXNSR0IArs4c6QAAAARnQU1BAACx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)
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