摘要:18.在函数f(x)=x+2的图象上. ∴an+1=an+2. ∴an+1-an=2. ∴{an}是以a1=1为首项.2为公差的等差数列. ∴an=2n-1. (2)由题易知bn==.则Sn=++-++.① Sn=++-++.② ①-②得Sn=+++-+-=+-=-. 则Sn=1-.
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已知函数f(x)=(x-1)2,g(x)=4(x-1),数列{an}是各项均不为0的等差数列,其前n项和为Sn,点(an+1,S2n-1)在函数f(x)的图象上;数列{bn}满足b1=2,bn≠1,且(bn-bn+1)·g(bn)=f(bn)(n∈N+).
(1)求an并证明数列{bn-1}是等比数列;
(2)若数列{cn}满足cn=
,证明:c1+c2+c3+…+cn<3.
已知函数f(x)=(x-1)2,g(x)=4(x-1),数列{an}是各项均不为0的等差数列,其前n项和为Sn,点(an+1,S2n-1)在函数f(x)的图象上;数列{bn}满足b1=2,bn≠1,且(bn-bn+1)·g(bn)=f(bn)(n∈N+).
(1)求an并证明数列{bn-1}是等比数列;
(2)若数列{cn}满足cn=
,证明:c1+c2+c3+…+cn<3.
已知函数f(x)=(x-1)2,g(x)=4(x-1),数列{an}是各项均不为0的等差数列,其前n项和为Sn,点(an+1,S2n-1)在函数f(x)的图象上;数列{bn}满足b1=2,bn≠1,且(bn-bn+1)·g(bn)=f(bn)(n∈N+).
(1)求an并证明数列{bn-1}是等比数列;
(2)若数列{cn}满足cn=
,证明:c1+c2+c3+…+cn<3.
(1)求an并证明数列{bn-1}是等比数列;
(2)若数列{cn}满足cn=