(9) If you multiply Equation (3.2.18) by you may easily derive the equation d+/=. Following our derivation of (3.2.18), we gave a second demonstration of why this equation must hold based on two alternate scenarios of paying back a loan of 1 made for n interest pe- riods. Think of another pair of ways of repaying a loan which give an alternative demonstration of d + = i Sni (10) in

(9) If you multiply Equation (3.2.18) by 1+i1, you may easily derive the equation d+si1=ai1. Following our derivation of (3.2.18), we gave a second demonstration of why this equation must hold based on two alternate scenarios of paying back a loan of 1 made for n interest periods. Think of another pair of ways of repaying a loan which give an alternative demonstration of d+si1=a/11