NPV = SUM_t Rt/(1+i)^t (wikipedia). This is similar to your formula. If Rt=constant for all t and t is infinite (hence in perpetuity), the formula simplifies to

NPV = SUM_t Rt/(1+i)^t (wikipedia). This is similar to your formula. If Rt=constant for all t and t is infinite (hence in perpetuity), the formula simplifies to what I have. More info can also be found here: http://www.investopedia.com/walkthrough/corporate-finance/3/discounted-cash-flow/perpetuities.aspx http://www.investopedia.com/walkthrough/corporate-finance/3/...