已知等差数列S10=100,S100=10,则S110=多少

2025-06-26 19:38:26
推荐回答(2个)
回答1:

S100- S10=10-100=- 90
a11+a12+...+a100=- 90
45(a11+a100)=- 90
a11+a100=- 2

a1+a110=a11+a100
s110=(a1+a110)*110/2= -110

回答2:

S110=-110