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已知数列{an}的前n项和Sn=2n2+2n,数列{bn}的前n项和Tn=2-bn.(Ⅰ)...
试题详情
已知数列{a
n}的前n项和S
n=2n
2+2n,数列{b
n}的前n项和T
n=2-b
n.
(Ⅰ)求数列{a
n}与{b
n}的通项公式;
(Ⅱ)设c
n=
,求证数列{c
n}的前n和R
n<4;
(III)设c
n=a
n+(-1)
nlog
2b
n,求数列{c
n}的前2n和R
2n.
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