题目

已知定义在上的奇函数，当时，.（1）求的解析式；（2）若对任意的，不等式恒成立，求实数的取值范围. 答案：【答案】（1）；（2）.【解析】（1）时，，由题意，得到，再由奇函数的性质，即可得出结果；（2）先由题意得到在上单调递减，根据函数奇偶性，推出在上单调递减，再将不等式恒成立，转化为在上恒成立，进而可得出结果.（1）当时，，则，又因为为奇函数，所以，所以，所以.（2）因为当时，， Complete the dialogue with proper words or sentences． A：Good morning, madam! B：Good morning, sir! A：You look worried．(1)__________? B：My son got lost when I was talking with my friend in the park．I’ve looked for him everywhere, but I can’t find him．What shall I do? A：(2)__________．Tell us something about him, and we can help you． B：Thank you, sir． A：Now please tell me(3)__________． B：He’s six years old． A：(4)__________? B：He’s thin and tall with big eyes． A：What is he wearing today? B：He’s wearing a white T-shirt and blue jeans． A：(5)__________ ? B：It’s 13803677057． A：OK．We’ll call you as soon as we find him． B：Thank you very much．