The principal po is invested in an account that pays an annual interest rate r (written as a decimal), compounded n times per year. the formula for the amount of money in the account at the end of the first period is given by the formula: p=po(1+ r/n).explain why the amount of money in the account at the end of the first year is given by the formula with n as the exponent: p=po(1+ r/n)^n[o=0 placed at the bottom of the number]