题目

 --- Which of these two magazines will you take?   --- I’ll take     , in case the journey is boring. A. all            B. either      C. both       D. neither 答案：C已知（a＞0，且a≠1），（1）判断奇偶性，并证明；（2）求使f（x）＜0的x的取值范围．