Assume the firms unlevered cost of capital is 8%, its cost of debt is 4%, and it currently has a\ debt level of $800 million which is composed of a single large bank loan. The loan is structured\ firm will pay $200 million of principal at the end of each of the next 4 years. The firm has no\ plans to take on any additional new debt in the future. The corporate tax rate is 20%.\ (a) Calculate the value of the firm using the APV approach\ (b) Calculate the firms WACC as of the start of year 1, year 2, year 3, and year 4\ (c) Calculate the firms free cash flow to equity in years 1 through