皮皮学,免费搜题
登录
搜题
【单选题】
听力原文:W: Personnel Department. M: Hello. Could I speak to Mr. Smith, please? W: I'm afraid he's not at his desk now. M: Do you know when he'll be back? W: About three-thirty, I think. Can I take a message? M: Yes. Could you tell him Mike Jackson called? I'll call again later. W: Mr. Jackson, I will tell him. Mt Thank you. Bye-bye. W: Goodbye. (8)
A.
The Personnel Department.
B.
The Marketing Department.
C.
The Production Department.
D.
The R&D Department.
拍照语音搜题,微信中搜索"皮皮学"使用
参考答案:
参考解析:
知识点:
.
..
皮皮学刷刷变学霸
举一反三
【简答题】已知随机变量ξ~N(0,σ 2 ),已知P(ξ>2)=0.023,则P(|ξ|≤2)=______.
【简答题】已知随机变量 则P{2 。
【简答题】若复数z=(m 2 -1)+(m+1)i为纯虚数,则实数m的值等于______.
【简答题】已知随机变量X~B ,则P(X=2)=________.
【简答题】已知复数z=(1-m 2 )+(m 2 -3m+2)i,其中m∈R ( I)若复数z=0,求m的值; ( II)若复数z为纯虚数,求m的值; ( III)若复数z在复平面上所表示的点在第三象限,求m的取值范围.
【单选题】已知随机变量X P(2),则D(X)等于()
A.
2
B.
4
C.
1
D.
8
【简答题】已知随机变量 ξ 的分布列为 P ( = k )= , k =1、2、3、4,则 P (2$amp; ≤4)等于_______________
【单选题】已知随机变量 X ~ N (1,4)且 P ( X <2)=0.72,则 P (1$amp; X<2)等于(  ).
A.
0.36
B.
0.16
C.
0.22
D.
0.28
【简答题】若复数z=(m 2 -m-2)+(m+1)i(为虚数单位)为纯虚数,其中m∈R,则m=______.
【简答题】若复数 z =( m 2 -1)+( m +1) i 为纯虚数,则实数 m 的值等于____