please help with the following questions....see attachment

5. a. Explain why the yield on a bond that trades at a discount exceeds the bond's coupon rate. b. Why are longer-term bonds more sensitive to changes in interest rates than shorter term bonds? c. Does the bond's YTM determine its price or does the price determine the YTM? 6. Alibaba Company Limited sold an issue of bonds with a 10-year maturity, a $1,000 par value, a 10 percent coupon rate, and semiannual interest payments. a. Two years after the bonds were issued, the going rate of interest on bonds such as these fell to 6 percent. At what price would the bonds sell? b. Suppose that 2 years after the initial offering, the going interest rate had risen to 12 percent. At what price would the bonds sell? c. Suppose the condition in part a existed. Further assume that the interest rate remained at 6 percent for the next 8 years. What would happen to the price of the bonds over time? Required: Determine the following for the company (a) Total Market value (b) After-tax Cost of Debt (c) Cost of Common Stock (d) Cost of Preferred Stock (e) WACC