题目

（2019·山东中考模拟）当﹣2≤x≤1时，关于x的二次函数y＝﹣（x﹣m）2+m2+1有最大值4，则实数m的值为（ ） A．2                B．2或         C．2或或   D．2或或 答案：B 【解析】 当m＜﹣2，x＝﹣2时，y最大＝﹣（﹣2﹣m）2+m2+1＝4，解得m＝﹣（舍）， 当﹣2≤m≤1，x＝m时，y最大＝m2+1＝4，解得m＝﹣； 当m＞1，x＝1时，y最大＝﹣（1﹣m）2+m2+1＝4， 解得m＝2， 综上所述：m的值为-或2， 故选B． 【点睛】 考查了二次函数的最值，函数的顶点坐标是最大值，利用函数的增减阅读短文，根据短文内容回答问题。If you have seen the movie “Pirates of the Caribbean (《加勒比海盗》)”, you must remember Johnny Depp who played the leading role as the captain (船长).“The Pirates” were such successful movies that they climbed to the top of all the most popular movie lists. At the same time, Depp became one of the most popular actors in Hollywood. Depp owns a large number of fans from the young to the old. Right now, Johnny Depp’s time has arrived. He has been named “favourite actor” for seven years in a row. Also, he was chosen as “the sexist (最性感的) man alive” by People Magazine.But success never came easily for him. It took a long time to make Depp remembered by the public. He was able to catch people’s eyes with roles in many movies from the family film like “Charlie and Chocolate Factory” to the serious film like “Public Enemies”, which was chosen as “best movies” for 2009.Johnny Depp is a person who never gives up trying a new start. Because of his increasing popularity, Depp was invited to play the screen role as the Mad Hatter in “Alice in Wonderland” directed by Tim Burton. “Depp can always bring the film surprise and we’re expecting his wonderful performances all the time,” he said.【1】Which role made Depp one of the most popular actors in Hollywood?__________________________________________________________________________【2】Who loves Depp, the young or the old?___________________________________________________________________________【3】Is “Charlie and the Chocolate Factory” a serious film?____________________________________________________________________________【4】How many movie names are mentioned in the passage?____________________________________________________________________________【5】What can you learn from Johnny Depp?_____________________________________________________________________________