已知等差数列{an}的前n项和为Sn,且满足Sn=n2﹣n.
(1)求an;
(2)设数列{bn}满足bn+1=2bn﹣an且b1=4,
(i)证明:数列{bn﹣2n}是等比数列,并求{bn}的通项;
(ii)当n≥2时,比较bn﹣1•bn+1与bn2的大小.
相关知识点
推荐套卷
已知等差数列{an}的前n项和为Sn,且满足Sn=n2﹣n.
(1)求an;
(2)设数列{bn}满足bn+1=2bn﹣an且b1=4,
(i)证明:数列{bn﹣2n}是等比数列,并求{bn}的通项;
(ii)当n≥2时,比较bn﹣1•bn+1与bn2的大小.