A.3 | B.6 | C.9 | D.36 |
15(a1+a 15) |
2 |
a5•a 11 |
(a8-3d)•(a 8+3d) |
9-9d 2 |
A.16 | B.24 | C.48 | D.128 |
A.(0,
| B.(
| C.[1,
| D.(
|
A.是等差数列但不是等比数列 |
B.是等比数列但不是等差数列 |
C.既是等比数列又是等差数列 |
D.既非等差数列又非等比数列 |
A.120 | B.105 | C.90 | D.75 |
A.m>k |
B.m=k |
C.m<k |
D.m与k的大小随q的值而变化 |
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