S2011 |
2011 |
S2008 |
2008 |
n(a1+an) |
2 |
Sn |
n |
a1+an |
2 |
S2011 |
2011 |
S2008 |
2008 |
a1+a2011 |
2 |
a1+a2008 |
2 |
a2011-a2008 |
2 |
3d |
2 |
S2011 |
2011 |
S2008 |
2008 |
3d |
2 |
2011×(2011-1)d |
2 |
2011×2010×2 |
2 |
x2-x+n |
x2+1 |
a | n |
1 |
2 |
Sn |
n+c |
dn |
(n+36)dn+1 |
A.-8 | B.8 | C.8或-8 | D.-
|
A.S10最小 | B.S9最大 | C.S8,S9最小 | D.S8,S9最大 |
A.a>0,d>0 | B.a>0,d<0 | C.a<0,d>0 | D.a<0,d<0 |
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