b) Suppose you want to calculate the present value of the final-year's interest tax shield for a project that has a life of four years. When should each of the formulas below be used? Explain the rationale for using each formula. Formula 1: PV (ITS) IT'S (1 + R)* Formula 2: PV (ITS) ITS (1 + R) Formula 3: PV (ITS) ITS (1 + R) (1 + R) b) Suppose you want to calculate the present value of the final-year's interest tax shield for a project that has a life of four years. When should each of the formulas below be used? Explain the rationale for using each formula. Formula 1: PV (ITS) IT'S (1 + R)* Formula 2: PV (ITS) ITS (1 + R) Formula 3: PV (ITS) ITS (1 + R) (1 + R)