二维随机变量(x,y)的概率密度为f(x,y)=e^-y,0

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二维随机变量(x,y)的概率密度为f(x,y)=e^-y,0二维随机变量(x,y)的概率密度为f(x,y)=e^-y,0二维随机变量(x,y)的概率密度为f(x,y)=e^-y,0fX(x)=∫(x~

二维随机变量(x,y)的概率密度为f(x,y)=e^-y,0
二维随机变量(x,y)的概率密度为f(x,y)=e^-y,0

二维随机变量(x,y)的概率密度为f(x,y)=e^-y,0
fX(x)=∫(x~无穷) f(x,y)dy =-e^(-y)|(x~无穷)=0-(-e^(-x))=e^(-x)
fY(y)=∫(0~y)f(x,y) dx =e^(-y) x |(0~y)= y e^(-y)