问GWD－1－9

falcons

Q9:

For all integers n, the function f is defined by f (n) = aⁿ, where a is a constant. What is the value of f (1)?

(1) f (2) = 100

(2) f (3) = -1,000

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT sufficient.

答案是B。可是我觉的statement (1)可以解出f(1)=10 或－10。为什么不是suggicient的呢。请大家帮忙解释一下， 非常感谢！

himba

先要明白DS题的要求，是问是否能求出确定的、唯一的解

既然都知道条件1可以解出两个解，那么答案不唯一，不能确定解，当然不选

smart

statement (1) ，f(1)不能得出唯一的答案。
故选B。