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A.Sk+ B.Sk+
C.Sk+ D.Sk+
设Sk=+++…+,则Sk+1为 ( )
(A)Sk+ (B)Sk++
(C)Sk+– (D)Sk+–
设Sk=+++…+,则Sk+1=( )
(A)Sk+
(B)Sk++
(C)Sk+-
(D)Sk+-
已知Sk表示{an}的前K项和,Sn―Sn+1=an(n∈N+),则{an}一定是_______。
A、等差数列 B、等比数列 C、常数列 D、以上都不正确