• 2022-06-25
    ‏设二维随机变量(X,Y)的联合分布函数为[img=358x53]1803da28eea1139.png[/img]则常数A=( )‎‏‎
    A: [img=11x43]1803da28f803a36.png[/img]
    B: [img=18x43]1803da2900f5c07.png[/img]
    C: [img=11x43]1803da290a57734.png[/img]
    D: [img=18x43]1803da2913fa238.png[/img]