Cost of debt using the approximation formula For the following $1,000-par-value bond, assuming annual interest payment and a 21% tax rate, calculate the after-tax cost to maturity using the approximation formula. (Click on the icon here in order to copy the contents of the data table below into a spreadsheet.) Life 10 years Underwriting fee $40 Discount (-) or premium (+) - $20 Coupon interest rate 9%