f(n)是O(2ⁿ)且g(n)是O(n²) A: f(n)g(n)是Ο(4ⁿ) B: f(n)+g(n)是Ο(n^4) C: f(n)+g(n)是Ο(2n²) D: f(n)g(n)是Ο(n^4)

已知线性卷积x(n)*h(n)={-15, 4, -3, 13, -4, 3, 2}。x(n)和h(n)的6点圆周卷积和x(n)⑥h(n)为（ ）。 A: {-13, 4, -3, 13, -4, 3} B: {-15, 4, -3, 13, -4, 3, 2} C: {-15, 4, -3, 13, -4, 3} D: {-15, 4, -3, 13, -4, 3, 2}

镭核经过m次α衰变、n次β衰变变成铅核，则（） A: m=4，n=4 B: m=5，n=3 C: m=4，n=3 D: m=5，n=4

下列程序段能分别正确显示1!、2!、3!、4!的值的是______。 A: For i = 1 To 4 n = 1 For j = 1 To i n = n * j MsgBox(n) Next jNext i B: For i = 1 To 4 For j = 1 To i n = 1 n = n * j Next j MsgBox(n)Next i C: n = 1For i = 1 To 4 For j = 1 To 4 n = n * j MsgBox(n) Next jNext i D: n = 1j = 1Do While j <= 4 n = n * j MsgBox(n) j = j + 1Loop

下列程序段能且只能显示1！、2！、3！、4！的值的是（ ）。 A: For i = 1 To 4 n = 1 For j = 1 To i n = n * j Next j MsgBox(n)Next i B: For i = 1 To 4 For j = 1 To i n = 1 n = n * j Next j MsgBox(n)Next i C: n = 1For i = 1 To 4 For j = 1 To 4 n = n * j MsgBox(n) Next jNext i D: n = 1j = 1Do While j <= 4 n = n * j j = j + 1LoopMsgBox(n)

下列程序段不能正确显示1！、2！、3！、4！的结果的是 。 A: For i = 1 To 4 For j = 1 To i n = 1 n = n * j Next j MsgBox( n)Next i B: Dim i%, j%, n%For i = 1 To 4 n = 1 For j = 1 To i n = n * j Next j MsgBox( n)Next i C: Dim j%, n%n = 1For j = 1 To 4 n = n * j MsgBox( n)Next j D: Dim j%, n%n = 1j = 1Do While j<=4 n=n*j MsgBox(n) j=j+1Loop E: Dim j%, n%n = 1j = 1Do n=n*j MsgBox(n) j=j+1Loop While j<=4

int n = 3; n = n + 4; n的值为多少 A: 3 B: 7 C: 4 D: 表达式错误

周期序列2sin(3πn/4+π/6)+3cosπn/4的周期N= ( ) 。 A: π/4 B: 8/3 C: 4 D: 8

能判断某一年n是否为闰年的表达式是 。 A: n%4==0&amp;&amp;n%100!=0||n%400==0 B: y%100!=0||y%4==0||y%400==0 C: n%4==0||n%100!=0||n%400==0 D: n%4==0&amp;&amp;n%100!=0&amp;&amp;n%400==0

用δ(n)及其延迟项表示序列x(n)={2, -3 , 4,1},结果为( ) A: x(n)=2δ(n)-3δ(n-1)+4δ(n-2)+δ(n-3 B: x(n)=2δ(n-1)-3δ(n)+4δ(n+1)+δ(n+2) C: x(n)=2δ(n+1)-3δ(n)+4δ(n-1)+δ(n-2) D: x(n)=2δ(n)-3δ(n+1)+4δ(n+2)+δ(n+3)