申論題

 Let X and Y be continuous randoun variables with the joint probability density function

, 0 ≤x<ㆀ,0≤y<∞, where c is a constant. Then c=   (a)  

E(XY²)=    (b)   ,and cov(X,Y)=    (c)   . Given the information that X = x, the

conditional probability density function of Y is =    (d)  . Now we let Z = X+Y

with the probability density function and. the corresponding mnoment generating function.Then =    (e)    and My(t) =   (f)   .