• 2022-07-26
    求每个周期信号[tex=1.643x1.357]Wfem9oxh0ZS7nZ3KGomKoQ==[/tex]的傅里叶变换[tex=2.5x1.357]NMTIzhVmnGHQGvCvBC6XCA==[/tex],并画出幅度频谱[tex=3.071x1.357]tcq04i8xobOSRu0T0xU9XyPkrWz08AQkOV8t8VZnBo0=[/tex]和相位频谱 [tex=2.071x1.357]c7xKbidtXvSXdazNy5Dxo9Lf4Vpl2j+DX2gAfq8UAb8=[/tex]。[tex=16.286x2.214]DAKw8ybhflb/AHcvWBlbR7pcTm+3EUtJ90ax2DKpBmtVaA3iAFZgqZ06kzGboeK4GiQVQ9kVaXk0i+zpNgbIdfMjfT2qFK8NOa5wtTOuZhM=[/tex]
  • 已知 [tex=21.357x1.571]VfYmFiq6mt5pAY6lm3zmpzAUJg02y7/LETx6cUIQyZw7k+pvGbZJtHsHi+gGxwS4sEjCaSazpUKeDv8yPqP78HcnBa3zXfoJIhcUthsxPYxPnjUCYMp5eGCeqxcDM8ifsXfLRk1GOKJJ8RoQLm6pa6uuhbrPW+S9xXEwzt8J9JV3dlYfJH9CqpSlg1/nYYVwaGKZ3HpXrvfWoZU870tJTGgbG40iX2R0/CdzVCVfC2MB+WX0cYGKy3aSAZsNji6S[/tex]所以 [tex=16.286x1.357]Ggm0/T9Kl1+E1fymXp6mTKjYSr6KrJdn4ulqsvxS0Xh4h+DIL/TiajaGlQzUpt9y48ueUrNllG2tDm4KjXRayA==[/tex][tex=16.714x2.214]DY7UekjPkAjnLhl3/i+b+sjVr8/Rd/qbZ6GBbBnFxBUAYunx7W+3qSH5JE+Zaq8ukgz5SXtLLOU91bovx8RhMiBmimpVzlLdrNB554O8gK6gtp6tU83Spg1T6VfN7zUl[/tex]

    内容

    • 0

      假设“☆”是一种新的运算,若3☆2=3×4,6☆3=6×7×8,x☆4=840(x>0),那么x等于: A: 2 B: 3 C: 4 D: 5 E: 6 F: 7 G: 8 H: 9

    • 1

      下面是图的拓扑排序的是?(多选)[img=340x240]1802faef6ebcc2a.png[/img] A: 2 8 0 7 1 3 5 6 4 9 10 11 12 B: 2 8 7 0 6 9 11 12 10 1 3 5 4 C: 8 2 7 3 0 6 1 5 4 9 10 11 12 D: 8 2 7 0 6 9 10 11 12 1 3 5 4

    • 2

      设DES加密算法中的一个S盒为: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 0 1 2 3 14 4 13 1 2 15 11 8 3 10 6 12 5 9 0 7 0 15 7 4 14 2 13 1 10 6 12 11 9 5 3 8 4 1 14 8 13 6 2 11 15 12 9 7 3 10 5 0 15 12 8 2 4 9 1 7 5 11 A: 1010 B: 0001 C: 1011 D: 0111

    • 3

      下面语句的输出结果是?range(len('HelloWorld')) A: [1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11] B: 11 C: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10] D: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]

    • 4

      当执行下面的语句定义一维数组a后,此数组的所有元素为 ( ) inta[10]; A.a[1],a[2],a[3],a[4],a[5],a[6],a[8],a[9],a[10],a[10] B.a[0],a[1],a[2],a[3],a[4],a[5],a[6],a[7],a[8],a[9] C.a[0],a[2],a[3],a[4],a[5],a[6],a[7],a[8],a[9],a[10] D.a[1],a[2],a [3],a[4],a [5],a [9],a [7],a [8],a [9],a [10],a [11]