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5. Let (A,B) be bivariate normal where E(A) = 0, E(B) = 0, Var(A) = 1, Var(B) = 1 and the correlation coeff. of (A,B) = p. a) If X = A & Y = B - pA, find the joint pdf of (A,B) b) Find the correlation coeff. between A & B2 Hint: if X ~ N(0,1), then E(X*) = 3