• 2022-06-09
    设随机变量 $\xi$ 具有对称的密度函数 $f(x)$,即$f(x)=f(-x)$,证明对任意 $h>0,有:[tex=16.0x5.714]qlmQA1D8xtk2KTRQ/XTaGu/EiNAMcSZvQOLN/o9oTzkJDDaZqPzVFFOEYV0IlvIxg+NLbN5HBxE9HqdnYcUMk7x3J71PLc6IhnZMY4AlQxXAfAOaQfAg5wIdOMyd2MjRq5Bg1tTortQBDyYNTTp6nTzqLiGnNc7VRx/woKeV7i0=[/tex]
  • (1) 由[tex=22.214x2.929]ZlC/K4Fi26jq7k7YsEcCepZAFwpEmJSVYTup7nQhIzUX3xJtAGex4tCgAu2rFzm374mrtohtnadc6suBd+fafwgg9JvQhX5RY2zwX2twVaRIxhl53LNm4d5oOGOkA1BAEs25zgT4CgzepQ26zbQKj+vsa/ZoWvHsNC7qX+bPBx4=[/tex],令[tex=2.643x1.143]2CE25a1Z4g/MBHRtpb79EA==[/tex],利用[tex=1.857x1.357]bZ4KhrFbnCaidqbMGQZfww==[/tex]为偶函数得[tex=19.571x2.929]GlxEPZfZL62qZ0fJJdLkMFOC/9kd4VSvHMhgvtMRt77+wKlvEL8CP2U0cGHSI+y/99QLJDB84jeWoPlAdFXAHvD0CPRloCGFAE8+0NCjHSjXKh3F4cZ5YT2fRo5ef3nO[/tex].同样由[tex=1.857x1.357]bZ4KhrFbnCaidqbMGQZfww==[/tex]为偶函数,得[tex=7.357x2.714]qN8fOJEmxCPwE8y3sw7Sc776NiHc4P2MuREbqro7jyo2Q3WJ3lzQ8RKYKtw0QgEE+aNcm3jOVguMctHzlbH8lQ==[/tex],得[tex=22.429x6.071]ifE9NWj3X6IpRVSt3T5ITov4CZ7F53WBTOmPWMAtOidw4OFcx0ipJGksnuzNZ9vZF2mbQZ4qWkbGqb3eUqYsIW1xtvbbk+sJJQA5mc3A2ck3iWmmohDK1jZPjxHFvWdB9Oa0BetndFASxw6X38QSTjMjY8dfOlsbbKeJnbcB+trA9nTvxDIVzh4+XiKlsQdTa1cjsNLsza8mq21+1C41mspaaWAC61oMWyAT7vsriBnqFUCIy5QRHia2wdWmdWH6cwJci4H+WLaW4P+m/lpETg==[/tex]综上(1)得证.(2) 由(1),[tex=18.143x3.071]ifE9NWj3X6IpRVSt3T5ITnvqkAcsvI7THoawsH8J0dUc/58FgxMSHcRvc7pMRKgjHTEw7sY8uzevcG+iDquPkUxH2qpRL99wqac20HW1xyXYdi8yWgk8giW+bdw/aNHoRpLauh4fQWQA6egjruvvaw==[/tex](3) 由(1),[tex=18.5x4.5]ifE9NWj3X6IpRVSt3T5ITg5qO/mvcNcy75aeDBtT3RZODreAyh1JCY+V9WaLOnjglnFF+n5KLmeUOKTYgPGl63W1UFZo27eBAldWr+RBKXIQ/JRiLJKdkkr5b4lpuvDAjufTrEO2X0PD0hR3tvqHMyXUtJdw69OiNeik9bB4Yyw=[/tex]

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    • 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

      以下创建数组的方式错误的是() A: shortx[];x={1,2,3,4,5,6}; B: shortx[]=newshort[6];x[0]=9;x[1]=8;x[2]=7;x[3]=6;x[4]=5;x[5]=4; C: shortx[]=newshort[6];intlen=x.length;for(inti=0;i

    • 2

      3.设函数$f(x)={{x}^{4}}\sin x$,则${{f}^{(9)}}(0)=$( )。 A: $\frac{9!}{5!}$ B: $\frac{5!}{9!}$ C: $\frac{1}{5!}$ D: $0$

    • 3

      \(二次型f(x)=x^{T}\begin{bmatrix} 1 & 2 & 3 \\ 4 & 5 & 6 \\ 7 & 8 & 9 \end{bmatrix}x的秩为\)

    • 4

      ‌下面说法错误的是( )。‌‌知识点:列表推导式‌ A: dict([(x, x**2) for x in range(6)]) 创建的字典是{0: 0, 1: 1, 2: 4, 3: 9, 4: 16, 5: 25} B: [[x*3+y for y in range(1,4)] for x in range(3)] 创建的是二维列表 [[1, 2, 3], [4, 5, 6], [7, 8, 9]] C: number = [-2, 4, 6, -5]string = 'ab'z = [(i, j) if i>0 else (-i, j) for i in number for j in string]这段代码创建的列表为[(2, 'a'), (2, 'b'), (4, 'a'), (4, 'b'), (6, 'a'), (6, 'b'), (5, 'a'), (5, 'b')] D: ' '.join([i for i in range(1,11)])的运算结果为字符串'1 2 3 4 5 6 7 8 9 10'