数列选择题专项训练
(限时 30分钟)
姓名: 学号:
(1)数列1,3,…,82,…是( )
(A )等差数列,而不是等比数列 (B )等比数列,而不是等差数列
(C )等差数列,又是等比数列 (D )即非等差数列,也非等比数列
(2)已知为等比数列,当时,则( )
(A )6 (B )7 (C )8 (D )9
(3)设数列的前
项的和为
则
( )
(A )
(B )
(C )
(D )
(4)在等差数列
中,已知
,184=
=S S 设则( )
(A )8 (B )9 (C )10 (D )11
(5)已知首项为1的无穷等比数列的所有项之和为3,
为其公比,则
=( )
(A ) (B )
(C )
(D )
(6)设无穷等比数列所有奇数项之和为15,所有偶数项之和为
为其首项,则
( )
(A ) (B )
(C )
(D )
(7)设数列的前项和如果则
(A ) (B )
(C )
(D )
(8)已知成等比数列,如果和都成等差数列,则
( )
(A )1 (B )2 (C )3 (D )4
(9)已知{}n a 是等差数列,切,39852=++a a a 则9821a a a a ++++ 的值是( )
(A )117 (B )114
(C )111 (D )108
10.等比数列{}n a 中,各项和2
1
21=++++ n a a a ,则1a 的取值范围是( )
(A )(0。+∞) (B )(-∞,1)
(C )(0,1) (D )(0,2
1)∪()1,21
数列选择题专项训练答案
DCABA BCBAD