题目

已知函数为偶函数,其图象上相邻的两个最高点之间的距离为． （Ⅰ）求的解析式  ；    （Ⅱ）若  ，求  的值． 答案：（Ⅰ）    （Ⅱ）   解析:（Ⅰ）图象上相邻的两个最高点之间的距离为, ,  则. .                                          ……2分 是偶函数, ,   又，． 则 ．                                                …5分 （Ⅱ）由已知得，． 则．           �It suddenly ________ me that the story might have ________ in a small town in Nevada in 1990. [　　] A．thought of; taken placeB．stuck; been going on C．occurred to; happenedD．reminded; been up