If you deposit $400 at the end of each month into an account earning 8% interest compounded monthly, what is the value of the account at the end of 5 years? 10 years? Referring to find the smallest...

If you deposit $400 at the end of each month into an account earning 8% interest compounded monthly, what is the value of the account at the end of 5 years? 10 years?

Referring to find the smallest value of
 in terms of P and i that will fund a perpetual annuity, that is, an annuity for which
 for all n. What is the value of
 in this case?