摘要:2)若正整数n, m, k成等差数列.求证: +≥.
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设正项数列{an}的前项和为Sn,q为非零常数.已知对任意正整数n,m,当n>m时,Sn-Sm=qm•Sn-m总成立.
(1)求证数列{an}是等比数列;
(2)若正整数n,m,k成等差数列,求证:
+
≥
.
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(1)求证数列{an}是等比数列;
(2)若正整数n,m,k成等差数列,求证:
| 1 |
| Sn |
| 1 |
| Sk |
| 2 |
| Sm |
设正项数列{an}的前项和为Sn,q为非零常数.已知对任意正整数n,m,当n>m时,Sn-Sm=qm•Sn-m总成立.
(1)求证数列{an}是等比数列;
(2)若正整数n,m,k成等差数列,求证:
+
≥
.
查看习题详情和答案>>
(1)求证数列{an}是等比数列;
(2)若正整数n,m,k成等差数列,求证:
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(2013•黄浦区二模)已知数列{an}具有性质:①a1为整数;②对于任意的正整数n,当an为偶数时,an+1=
;当an为奇数时,an+1=
.
(1)若a1=64,求数列{an}的通项公式;
(2)若a1,a2,a3成等差数列,求a1的值;
(3)设a1=2m-3(m≥3且m∈N),数列{an}的前n项和为Sn,求证:Sn≤2m+1-m-5.( )
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| an |
| 2 |
| an-1 |
| 2 |
(1)若a1=64,求数列{an}的通项公式;
(2)若a1,a2,a3成等差数列,求a1的值;
(3)设a1=2m-3(m≥3且m∈N),数列{an}的前n项和为Sn,求证:Sn≤2m+1-m-5.( )