设二维随机变量(X,Y)的概率密度为f(x,y)求F(x,y) 设随机变量X-N(0 1)求Y=e^x概率密度?

\u8bbe\u4e8c\u7ef4\u968f\u673a\u53d8\u91cf(X,Y)\u7684\u6982\u7387\u5bc6\u5ea6\u4e3af(x,y)=2,0<=x<=1,0<=y<=x,f(x,y)=0,\u5176\u4ed6\uff0c\u6c42E(X+Y)

\u89c1\u56fe

\u76f4\u63a5\u7528\u516c\u5f0f\u6cd5\uff0c\u7b80\u5355\u5feb\u6377\uff0c\u7b54\u6848\u5982\u56fe\u6240\u793a





这个你是不是忘了书上的啊
f(x,y)=Fxy(x,y),就是F(x,y)对x,y求偏导得到的,那么F(x,y)就是 f(x,y)对x积分 从负无穷大积到x,然后再对y积分,从负无穷大积到y

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