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Question 2 (20 points = 10 + 10). The random variables X1 and X 2 have the following joint probability density function 22 $121a$221 0 otherwise. a) Use the change of variables (Jacobian) technique to compute the joint probability density function fy1 ,y2 (y1, m) of the following transformed random variables Y1=X1X2 X1 Y = _. 2 X2 Hint: Watch out for existence of an inequality between yl and y2 when specifying the support of fY1,Y2 (311,342)- b) Derive the marginal probability density function f X1 (931)