已知數(shù)列{an}的前n項(xiàng)和為Sn,且Sn=2n2+n,n∈N*,數(shù)列{bn}滿足an=4log2bn+3,n∈N*.

(1)求an,bn;

(2)求數(shù)列{an·bn}的前n項(xiàng)和Tn.

設(shè)Sn為數(shù)列{an}的前n項(xiàng)和,已知a1≠0,2an-a1=S1·Sn,n∈N*.

(1)求a1,a2,并求數(shù)列{an}的通項(xiàng)公式;

(2)求數(shù)列{nan}的前n項(xiàng)和.

等差數(shù)列{an}中,a7=4,a19=2a9.

(1)求{an}的通項(xiàng)公式;

(2)設(shè)bn=,求數(shù)列{bn}的前n項(xiàng)和Sn.

設(shè)數(shù)列{an}滿足a1=2,a2+a4=8,且對(duì)任意n∈N*,函數(shù)f(x)=(an-an+1+an+2)x+an+1cos x-an+2sin x滿足

f′=0.

(1)求數(shù)列{an}的通項(xiàng)公式;

(2)若bn=2(an+),求數(shù)列{bn}的前n項(xiàng)和Sn.

設(shè)等差數(shù)列{an}的前n項(xiàng)和為Sn,且S4=4S2,a2n=2an+1.

(1)求數(shù)列{an}的通項(xiàng)公式;

(2)設(shè)數(shù)列{bn}滿足++…+=1-,n∈N* ,求{bn}的前n項(xiàng)和Tn.

正項(xiàng)數(shù)列{an}滿足-(2n-1)an-2n=0.

(1)求數(shù)列{an}的通項(xiàng)公式an;

(2)令bn=,求數(shù)列{bn}的前n項(xiàng)和Tn.

已知等差數(shù)列{an}的前n項(xiàng)和Sn滿足S3=0,S5=-5.

(1)求{an}的通項(xiàng)公式;

(2)求數(shù)列的前n項(xiàng)和.

{an}滿足an+1+(-1)nan=2n-1,則{an}的前60項(xiàng)和為(　　)

(A)3690 (B)3660 (C)1845 (D)1830

數(shù)列{an}的通項(xiàng)公式an=ncos,其前n項(xiàng)和為Sn,則S2012等于(　　)

(A)1006 (B)2012 (C)503  (D)0

已知數(shù)列{an}的前n項(xiàng)和為Sn,a1=1,Sn=2an+1,則Sn等于(　　)

(A)2n-1 (B)n-1  (C)n-1  (D)