• 2021-04-14
    已知信号的频谱,则信号的频谱为/sqp/img?f=28b83f2373a70f8139a2d5c37fc443d1.files%2Fimage001.png28b83f2373a70f8139a2d5c37fc443d1.files/image002.png/sqp/img?f=28b83f2373a70f8139a2d5c37fc443d1.files%2Fimage003.png28b83f2373a70f8139a2d5c37fc443d1.files/image004.png/sqp/img?f=28b83f2373a70f8139a2d5c37fc443d1.files%2Fimage005.jpg
  • /sqp/img?f=28b83f2373a70f8139a2d5c37fc443d1.files%2Fimage009.png

    内容

    • 0

      f(x)=x2+bx+c,x∈R,有f(2+x)=f(2-x),则( ) A: f(1)<f(2)<f(4) B: f(2)<f(4)<f(1) C: f(4)<f(2)<f(1) D: f(2)<f(1)<f(4) E: f(1)<f(4)<f(2)

    • 1

      设函数f(x)=a|x|(a>0),且f(2)=4,则(  ) A: f(-1)>f(-2) B: f(1)>f(2) C: f(2)<f(-2) D: f(-3)>f(-2)

    • 2

      设f(x)为连续函数,则等于() A: f(2)-f(0) B: 1/2[f(11)-f(0)] C: 1/2[f(2)-f(0)] D: f(1)-f(0)

    • 3

      设个体域D={1,2}与公式∀x F(x)等价的命题公式是( ) A: F(1)∧F(2) B: F(1)→F(2) C: F(1)∨F(2) D: F(2)→F(1)

    • 4

      煤的普氏系数数值为()。 A: f=1~2 B: f=3~4 C: f=4~5 D: f=5~6