【判断题】引入负反馈后,虽然使放大电路的闭环增益减小,但是放大电路的许多性能指标得到了改善。
【简答题】Having been operated on twice for the disease, she ________________________________(身体十分虚弱,几乎站不起来). (weakened, barely)
【单选题】The old farmer was run down by a car. He was taken to the hospital and______ on by the chief surgeon right now.
【单选题】放大电路的闭环是指________________。
【简答题】本题满分16分. 已知 ,函数 ( ,求函数 的最小值.
【简答题】三、解答题:本大题共6小题,满分80分.解答须写出文字说明、证明过程和演算步骤. 16.(本小题满分12分) 已知函数 . (1)求 的值; (2)若 ,求 的值.