Use relation n n E Cov a;X,Y) = { = ai Cov (X,Y) i=1 And n K, = w, K, = i=1 to show that the beta factor By of a portfolio consisting of n securities with weights W1, ..., wn is given by n By = Wi i i=1 Where B1, Bn are the beta factor of the securities. Hint: recall that Cov (Ky ,KM). Cov (K,KM). Bu and Bi om OM =