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【简答题】
研究两个有限长序列x(n)与y(n)，当n＜0、n≥40和9＜n＜30时，x(n)为0，并且n＜10和n＞19时，y(n)为0，如图2-8所示。令ω(n)为x(n)与y(n)的线性卷积，g(n)为x(n)与y(n)的40点循环卷积，即
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【简答题】设函数f（x）= 3 sin2x+2cos 2 x． （1）求函数f（x）的最小正周期； （2）求函数f（x）的单调递增区间．
【简答题】设函数f（x）=a- 2 2 x +1 （1）求证：f（x）是增函数； （2）求a的值，使f（x）为奇函数； （3）当f（x）为奇函数时，求f（x）的值域．
【单选题】--- Look! __________ there are in the garden!
A.
- Let’s go there to take some photos.
B.
What a beautiful flower
C.
How a beautiful flower
D.
How beautiful flowers
E.
What beautiful flowers
【单选题】对四个三角形的全部内角进行观测，其观测值(内角和)分别为：180°00′18″、180°00′12″、179°59′48″、179°59′42″，则其观测值中误差为()。
A.
±0.0″
B.
±15.3″
C.
±5.5″
D.
±9.5″
【单选题】Many forms of etiquette are employed precisely to disguise those antipathies that arise from irreconcilable differences. (Para. 3)
A.
rules of polite behavior; strong dislikes
B.
directions for action; sharp disagreements
C.
words of advice; fundamental conflicts
D.
regulations of social activities; striking contrasts
【简答题】Social anxiety, in its many forms, is epidemic. About 40 percent of Americans think of themselves as shy, while only 20 percent say they have never suffered from shyness at some point in their lives. ...
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