摘要:22.设数列(1)求证:{bn}是等比数列,(2)求an,
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等比数列{an}同时满足下列三个条件:①a1+a6=33;②a3a4=32;③三个数4a2,2a3,a4依次成等差数列.
(Ⅰ)试求数列{an}的通项公式;
(Ⅱ)记bn=
,求数列{bn}的前n项和Tn;
(Ⅲ)设Sn是数列{an}的前n项和,证明
.
设数列{an}前和n为Sn,且(3-m)Sn+2man=m+3(n∈N*).其中m为常数,m≠-3,且m≠0.
(1)求证:{an}是等比数列;
(2)若数列{an}的公比q=f(m)=
且数列{bn}中,b1=a1,bn=
f(bn-1)(n∈N*,n≥2),求bn的表达式.
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(1)求证:{an}是等比数列;
(2)若数列{an}的公比q=f(m)=
| 2m |
| m+3 |
| 3 |
| 2 |
设数列{an}的首项a1=1,前n项和Sn满足关系式tSn-(t+1)Sn-1=t(t>0,n∈N*,n≥2).
(Ⅰ)求证:数列{an}是等比数列;
(Ⅱ)设数列{an}的公比为f(t),作数列{bn},使b1=1,bn=f(
)(n∈N*,n≥2),求数列{bn}的通项公式;
(Ⅲ)数列{bn}满足条件(Ⅱ),求和:b1b2-b2b3+b3b4-…+b2n-1b2n-b2nb2n+1. 查看习题详情和答案>>
(Ⅰ)求证:数列{an}是等比数列;
(Ⅱ)设数列{an}的公比为f(t),作数列{bn},使b1=1,bn=f(
| 1 | bn-1 |
(Ⅲ)数列{bn}满足条件(Ⅱ),求和:b1b2-b2b3+b3b4-…+b2n-1b2n-b2nb2n+1. 查看习题详情和答案>>