摘要:19.等差数列{ }的各项为正整数.a1=3.前n项和为.等比数列{}中.b1=1.且b2·S2=16.b3是a1.a2的等差中项 (1)求与, (2)求证:
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等差数列{an}各项均为正整数,a1=3,前n项和为Sn,等比数列{bn}中,b1=1,且b2S2=64,{ba n}是公比为64的等比数列.
(1)求an与bn;
(2)证明:
…+
.
等差数列{an}的各项均为正整数,a1=3,前n项和为Sn,等比数列{bn}中,b1=1,且b2S2=64,{ban}是公比为64的等比数列.
(1)求{an}与{bn};
(2)证明:
+
+…+
<
.
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(1)求{an}与{bn};
(2)证明:
| 1 |
| S1 |
| 1 |
| S2 |
| 1 |
| Sn |
| 3 |
| 4 |
等差数列{an}的各项为正整数,a1=3,前n项和为Sn,等比数列{bn}中,b1=1,且b2•S2=16,b3是a1、a2的等差中项
(1)求an与bn;
(2)求证:
+
+…+
<
.
查看习题详情和答案>>
(1)求an与bn;
(2)求证:
| 1 |
| S1 |
| 1 |
| S2 |
| 1 |
| Sn |
| 3 |
| 4 |