A portfolio is comprised of two stocks A, and B. The position in stock A is valued at WA (in m) and has a daily standard deviation of gains and losses of A. The position in stock B is valued at w (in m) and has a daily standard deviation of gains and losses of OB. Returns in stock A and stock B have a correlation coefficient of p = Pab = Pba = 0. Denote by Cov = COVAB = COVBA the covariance between the two stocks and by the variance-covariance matrix. a) Define and obtain the algebraic expression of the covariance between the two stocks b) Define and obtain the algebraic expression of matrix i.e., the variance-covariance matrix c) Let w (w) be the column (row) vector of holdings. Using your answers to (a) and (b), show that the daily standard deviation of change in the portfolio value o (in ) is equal to: