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. Discount (-) or Coupon Underwriting for premium (+) Interest rate 20 years $25 - $20 The alter-tax cost of financing using the approximation formula is 0% (Round to two decimal places.) Life 9%