【单选题】听力原文: The US president's helicopter flew over the path of the deadly storm in the state of Alabama, where eight teenagers were killed Thursday in the collapse of a high school in the town of Enterpris...
【简答题】已知函数 f(x)= a? 2 x 2 x + 2 的图象过点 (0, 2 -1) . (1)求f(x)的解析式; (2)设P 1 (x 1 ,y 1 ),P 2 (x 2 ,y 2 )为y=f(x)的图象上两个不同点,又点P(x P ,y P )满足: OP = 1 2 ( O P 1 + O P 2 ) ,其中O为坐标原点.试问:当 x P = 1 2 时,y P 是否为定值?若是,求出y P...
【单选题】听力原文: The US president' s helicopter flew over the path of the deadly storm in the state of Alabama, where eight teenagers were killed Thursday in the collapse of a high school in the town of Enterpri...