Question

2. Prove that if X, Y have a joint density, then for any Be B, f(y, x) JB f(x)

Answer 1

   As conditional probability says that,    
P(A/B)

P(B)

And also, X, Y have a joint density, which says   

f (y, x))dady

Therefore,     $\large P(Y\epsilon B/X=x)=\int_{B}^{ } \ \ f_{Y/X=x}(y,x)dy$

                                                         $= \int_{B}^$  
rz
                      and    
BEB1