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
设二维随机变量(X,Y)的概率密度为-|||-f(x,y)= { ,0lt ylt 2 0, .
70.设二维随机变量(X,Y)的概率密度为-|||-f(x,y)= ) 1, 0lt xlt 1, 0lt ylt 2x 0, .-|||-求:(1)
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
4.3 设二维随机变量(X,Y)的概率密度为-|||-f(x,y)= ) k,0lt (x)^2lt ylt xlt 1 0, ,
5.设随机变量(X,Y)的概率密度为-|||-f(x,y)= ) k(6-x-y),0lt xlt 2,2lt ylt 4 0,.
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
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
18.设随机变量(X,Y)的概率密度为-|||-f(x,y)= ) 3x,0lt xlt 1,0lt ylt x 0 .-|||-求边缘概率密度,并问X和