A pair of random variables has a joint PDF specified by
fX,Y(x,y) = dexp(-(ax2+bxy+cy2)).
(a) Find the constant in terms of ,a , b and c . Also, find any restrictions needed for a , b and c themselves for this to be a valid PDF.
(b) Find the marginal PDFs fX(x) and fY(y).
(c) Find Pr(X>Y) .