设Sn是等差数列{an}的前n项和,8a1+a4=0,则S4S2=(  )A.-15B.14C.-16D.1

2024-12-05 05:42:35
推荐回答(1个)
回答1:

在等差数列{an}中,设其公差为d,由8a1+a4=0,得:8a1+a1+3d=0,
即d=-3a1

S4
S2
4a1+
4×(4?1)d
2
2a1+d
4a1+6d
2a1+d
=
4a1?18a1
2a1?3a1
=14

故选B.