A.1项                  B.k项                C.2^k-1项           D.2^k项

A.1+＜2                                 B.1+=2

C.1+＜2                                       D.1+＜3

A.2k+1                  B.            C.2(2k+1)         D.

A.假设n=2k+1时正确,再推n=2k+3时正确

B.假设n=2k-1时正确,再推n=2k+1时正确

C.假设n=k时正确,再推n=k+1时正确

D.假设n≤k(k≥1)时正确,再推n=k+2时正确(以上k∈N^*)

A.a_k+                                  B.a_k+

C.a_k+                                  D.a_k+

A.n+1                   B.n                   C.n-1              D.n-2

(1)当n=1时,≤1+1,不等式成立;

(2)假设n=k(k∈N^*)时不等式成立,即＜k+1,则n=k+1时,

=(k+1)+1,∴当n=k+1时,不等式成立.

上述说法

A.过程全都正确                                B.n=1验得不正确

C.归纳假设不正确                              D.从n=k到n=k+1的推理不正确

A.5                               B.大于1小于10的某个整数

C.10                            D.大于10的某个整数