题目

任务型阅读 Bollywood: the Hollywood of India You might be surprised to learn that India produces about 800 movies a year, and that number continues to grow. Just as the movie Capital of the United States is Hollywood, the movie capital of India is Bombay (孟买), but it is usually called Bollywood, a combination(结合) of the words Bombay and Hollywood. All Bollywood movies are thought complete with a few songs and dances. In fact, music is an important part of Bollywood movies. Even a bad movie can still do well if the music is good. Music directors are sometimes more popular th已知函数f（x）=x2-2ax+5（a＞1）．（1）若f（x）的定义域和值域均是[1，a]，求实数a的值；（2）若对任意的x1，x2∈[1，a+1]，总有|f（x1）-f（x2）|≤4，求实数a的取值范围．