> 1 - ((1-45000)/45000)^(36510) = 0.08 I think you mean: 1 - ((45000-1)/45000)^(365*10) = 0.08 Whilst it doesn't matter if the exponent is even (such as

> 1 - ((1-45000)/45000)^(36510) = 0.08 I think you mean: 1 - ((45000-1)/45000)^(365*10) = 0.08 Whilst it doesn't matter if the exponent is even (such as 3650 above) using (1-45000)/45000 will give a wrong estimation for odd exponents.