Suppose that an account offers continuously compounded interest at an annual rate r and that withdrawals of size P are made at the end of each month. If the account is drawn down to zero after N...

Suppose that an account offers continuously compounded interest at an annual rate r and that withdrawals of size P are made at the end of each month. If the account is drawn down to zero after N withdrawals, show that the value of the account after n withdrawals is