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
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举一反三
- 已知g(0)=1,f(2)=3,f’(2)=5,等于(). A: 1 B: 2 C: 3 D: 5
- 如果f(a+b)=f(a)f(b)且f(1)=2,则f(2)f(1)+f(4)f(3)+f(6)f(5)=( )
- 已知函数f(x)满足:f(a+b)=f(a)•f(b),f(1)=2,则f2(1)+f(2)f(1)+f2(2)+f(4)f(3)+f2(3)+f(6)f(5)+f2(4)+f(8)f(7)=______.
- f(t)为原始信号,f1(t)为变换信号,则f1(t)的表达式是( )。[img=722x219]17de73b5129ea9f.png[/img] A: f(t/2 + 1) B: f(-t/2 - 1) C: f(-2t+1) D: f(-t/2 + 1)
- f(t)为原始信号,f1(t)为变换信号,则f1(t)的表达式是( )。[img=722x219]1803709447eacc9.png[/img] A: f(t/2 + 1) B: f(-t/2 - 1) C: f(-2t+1) D: f(-t/2 + 1)
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