Exercise 4. Show that the Macaulay's duration weights (as defined in the notes) sum up to 1 (present the algebra used to obtain this result). Explain how the size of the cash flow at each pe- riod, coupon and principle payments, (you may consider all other variables as constants) affect the size of those weights and relate this to the value of the duration. Exercise 4. Show that the Macaulay's duration weights (as defined in the notes) sum up to 1 (present the algebra used to obtain this result). Explain how the size of the cash flow at each pe- riod, coupon and principle payments, (you may consider all other variables as constants) affect the size of those weights and relate this to the value of the duration