If X and Y are any two independent continuous random variables whose probability density is [img=41x25]1803dc1d154ea64.png[/img] and [img=38x26]1803dc1d1dd7772.png[/img],and whose distribution function is [img=47x25]1803dc1d26f6f50.png[/img] and [img=42x25]1803dc1d300d282.png[/img],then [img=47x25]1803dc1d26f6f50.png[/img] + [img=42x25]1803dc1d300d282.png[/img] must be the distribution function of a random variable.

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2022-06-07

If X and Y are any two independent continuous random variables whose probability density is [img=41x25]1803dc1d154ea64.png[/img] and [img=38x26]1803dc1d1dd7772.png[/img],and whose distribution function is [img=47x25]1803dc1d26f6f50.png[/img] and [img=42x25]1803dc1d300d282.png[/img],then [img=47x25]1803dc1d26f6f50.png[/img] + [img=42x25]1803dc1d300d282.png[/img] must be the distribution function of a random variable.

答案：

错

举一反三

内容

0
设随机变量X服从均值为2的指数分布，X的分布函数为F(x)，数学期望为E(X)，方差为D(X)，则以下结果正确的是 A: [img=128x28]18033e117e9725e.png[/img] B: D(X)=4 C: P(X<2︱X>1)=F(1) D: P(X>2︱X>1)= F(1) E: [img=112x27]18033e11879f263.png[/img] F: D(X)=E(X) G: P(X≤2︱X>1)= F(2) H: [img=82x27]18033e1190d2ef2.png[/img]
1
设随机变量X服从均值为2的指数分布，X的分布函数为F(x)，数学期望为E(X)，方差为D(X)，则以下结果正确的是 A: [img=128x28]18036372a260d4c.png[/img] B: D(X)=4 C: P(X<2︱X>1)=F(1) D: P(X>2︱X>1)= F(1) E: [img=112x27]18036372aa45c90.png[/img] F: D(X)=E(X) G: P(X≤2︱X>1)= F(2) H: [img=82x27]18036372b2a31e1.png[/img]
2
设随机变量X服从均值为2的指数分布，X的分布函数为F(x)，数学期望为E(X)，方差为D(X)，则以下结果正确的是 A: [img=128x28]18032aad1d9bd98.png[/img] B: D(X)=4 C: P(X<2︱X>1)=F(1) D: P(X>2︱X>1)= F(1) E: [img=112x27]18032aad25f3c0b.png[/img] F: D(X)=E(X) G: P(X≤2︱X>1)= F(2) H: [img=82x27]18032aad2e07f09.png[/img]
3
可导函数f(x)，对任意的x,y恒有f(x+y)=f(x)f(y)，且f'(0)=1,则f(x)等于 A: [img=60x19]1802fb229b3bc18.png[/img] B: [img=55x46]1802fb22a3b7107.png[/img] C: [img=17x19]1802fb22abf3c5e.png[/img] D: [img=49x23]1802fb22b545827.png[/img]
4
随机变量 X 服从均匀分布[img=296x96]17de89393460b92.png[/img]则D(X)=( ). A: 4.5 B: 25/12 C: 1/5 D: 1