举一反三
- 已知[img=124x63]1803d9164101fc5.png[/img]，矩阵[img=123x28]1803d916494ccce.png[/img]，则[img=40x22]1803d9165227338.png[/img]【 】
- 已知[img=124x63]1803d9168925e7d.png[/img]，矩阵[img=123x28]1803d91691d4548.png[/img]，则[img=40x22]1803d9169b9a83d.png[/img]【 】
- 已知矩阵A=[img=424x296]17d6020868200e3.png[/img]有特征值[img=516x95]17d602087152a96.png[/img]，则x=（ ）。 A: 2 B: 4 C: －2 D: －4
- 已知随机变量X的分布函数为[img=136x49]1803b69024c8270.png[/img] ，则X的均值和方差分别为 A: E(X)=2, D(X)=4 B: E(X)=4, D(x)=2 C: [img=162x43]1803b6902cd8bfb.png[/img] D: [img=162x43]1803b69034d9ffd.png[/img]
- 已知矩阵[img=126x63]18034a7cde5633e.png[/img]相似于矩阵[img=142x71]18034a7ce8de7be.png[/img],则 A: x=-2, y=-1 B: x=2, y=-1 C: x=1,y=-2 D: x=-1,y=-2
内容
- 0
设随机变量X服从泊松分布，已知P(X=1)=P(X=2)，则P(1.5<X<4)= A: [img=100x98]1803b3b73611604.png[/img] B: [img=92x99]1803b3b7409092a.png[/img] C: [img=105x98]1803b3b74af8409.png[/img] D: [img=83x95]1803b3b755583a2.png[/img]
- 1
已知信号 x ( t )在 [img=75x22]18038ea77bb180f.png[/img] 时取值为[img=77x25]18038ea783d9313.png[/img]，其余为零，则x ( t )的能量为 A: [img=31x22]18038ea78cf2a5e.png[/img] B: [img=54x22]18038ea795de8fb.png[/img] C: [img=40x22]18038ea79e06c41.png[/img] D: [img=54x22]18038ea7a65b231.png[/img]
- 2
设[img=162x19]17e0ab913cc7ca8.jpg[/img]且X，Y相互独立，则[img=84x19]17e0ab9147a14b0.jpg[/img]. A: 14 B: 22 C: 32 D: 40
- 3
Which of the following propositions is false,set A = {x,x is an integer and[img=60x23]1803a1c6eebb7a3.png[/img]} ? ( ) A: [img=113x25]1803a1c6f77ce06.png[/img] B: [img=139x25]1803a1c7001fe79.png[/img] C: [img=51x22]1803a1c70863f61.png[/img] D: {x|x is an integer and |x| 4}[img=33x22]1803a1c711a7c63.png[/img]
- 4
Which of the following propositions is false,set A = {x,x is an integer and [img=60x23]1803a1c503ffa04.png[/img]} ? ( ) A: [img=113x25]1803a1c50cc3162.png[/img] B: [img=139x25]1803a1c514e60ea.png[/img] C: [img=51x22]1803a1c51dd52ef.png[/img] D: {x|x is an integer and |x| <4} [img=33x22]1803a1c525cf1bd.png[/img]