21.设随机变量(X Y)的概率密度为-|||-f(x,y)= ) x+y, 0lt xlt 1,0lt ylt 1 0, .-|||-,-|||-分别
21.设随机变量(X,Y)的概率密度为-|||-f(x,y)= ) x+y, 0lt xlt 1,0lt ylt 1 0, .-|||-,-|||-分别
28.设二维随机变量(X,Y)的联合密度函数为-|||-,-|||-p(x,y)= ) 3x, 0lt ylt xlt 1 0, .-|||-求X与Y的
9.设二维随机变量(x,y)的联合密度函数为 f(x,y)= ) Axy,0lt xlt 1,0lt ylt x 0;
设随机变量(X,Y)的概率密度为f(x,y)= ) k, 0lt xlt 1,0lt ylt x, 0, .-|||-.试确定常数k,并求E(XY).设
4.设二维随机变量(X,Y)的概率密度为-|||-f(x,y)= ) Axy,0lt xlt 1,0lt ylt 1 0 ;-|||-(4)(X,Y)的分
[题目]设二维随机变量(X,Y)的概率密度为-|||-f(x,y)= ) 2-x-y,0lt xlt 1,0lt ylt 1 0 .-|||-(1)求 (
设二维随机变量(X,Y)的密度函数: f(x,y)= ) Ay,0lt xlt (y)^2,0lt ylt 1 0
1.设二维随机变量(X,Y)的联合密度为-|||-f(x,y)= dfrac (4)(9)(x+1)(y+1) 0lt xlt 1,0lt ylt 1-|||
设随机变量(X,Y )的概率密度函数为-|||-f(x,y)= ) 3x,0lt xlt 1,0lt ylt x 0, .-|||-求:(1) Z=X+Y