n2+n+1 |
anan+1 |
5×4 |
2 |
3 |
5 |
3 |
5 |
3 |
5 |
3 |
5 |
3 |
5 |
n2+n+1 | ||||
|
25 |
9 |
n2+n+1 |
n(n+1) |
25 |
9 |
1 |
n |
1 |
n+1 |
25 |
9 |
1 |
2 |
1 |
2 |
1 |
3 |
1 |
99 |
1 |
100 |
25 |
9 |
1 |
100 |
1111 |
4 |
A.d<0 |
B.a7=0 |
C.S9>S5 |
D.S6 和S7都是 Sn 的最大值 |
A.8 | B.9 | C.10 | D.11 |
A.10 | B.21 | C.161 | D.171 |
© 2017-2019 超级试练试题库,All Rights Reserved.