时间:2023-12-31 15:21:48 下载该word文档
一、等差数列选择题
1.设等差数列an的前n项和为Sn,若a2a9a38,则S15( ) A.60 B.120 C.160 D.240
2.已知数列{an}的前n项和为Sn,且满足an22an1an,a54a3,则S7( ) A.7 B.12 C.14 D.21
3.等差数列an中,已知a1a4a739,则a4( ) A.13 B.14 C.15 D.16
4.设Sn是等差数列an的前n项和.若a1a4a76,则S7( ) A.10
B.8 C.12 D.14
5.在等差数列an中,a3a914,a23,则a10( ) A.11
B.10
C.6
D.3
6.已知数列an是等差数列,其前n项和为Sn,若a4a54,则S8( ) A.16 C.4 A.a5=4 B.a6=4 B.-16 D.-4 C.a5=2 D.a6=2
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