1 |
2 |
a5-a3 |
5-3 |
1 |
2 |
2 |
3 |
1 |
2 |
bn |
bn-1 |
1 |
3 |
2 |
3 |
1 |
3 |
2 |
3n |
2(2n-1) |
3n |
2(2n+1) |
3n+1 |
2(2n+1) |
3n+1 |
2(2n-1) |
3n |
8(1-n) |
3n+1 |
1 |
anan+1 |
A.它的首项是-2,公差是3 | B.它的首项是2,公差是-3 |
C.它的首项是-3,公差是2 | D.它的首项是3,公差是-2 |
A.9 | B.10 | C.11 | D.12 |
A.100 | B.210 | C.380 | D.400 |
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