If m and n are nonzero integers, is mn an integer?
(1) nm is positive.
(2) nm is an integer
Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
EACH statement ALONE is sufficient.
Statements (1) and (2) TOGETHER are NOT sufficient.
题目分析:
如果m>1且n<0,则~$m^n$~不是整数,例如,m=2,n=-1,则~$m^n=2^{-1}=1/4$~,不是整数
(1) 上述例子满足条件1,~$n^m=2$~为正,但~$m^n$~不是整数。
(2) 上述例子同时满足条件2,~$n^m=2$~为正,但~$m^n$~不是整数。
因此,本题答案为(E),两个条件结合起来也不能解题,必须提供新数据。
条件一不能得出n是正数,因为复数偶次方也是正数。
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