Answer to the 8a Question from Elena

The power is raised to the m-1, because of the time that the money is invested. I know this sounds confusing, but give me a second. Take a look at the chart, the first payment is a very "young" one, being that it has not been maturing in the investment for any time. Hence, the payment is not effected by interest. There for what ever period of time that the money is invested has to be decreased by one to account for the one year without a growth through interest.