I am aware of the formula that you mentioned PV = R. PVIFA(i%,N) yet since users may enter uneven cash flows for the annuity thus I am discounting each of the net cash flows with this formula PV = R. PVIF(i%,N)
since you brought up this issue, I am going to revamp the calculation to make room for both uneven and constant cash flows plus the option to select whether it is ordinary annuity or annuity due.
I got zillions of ideas yet I only make around $100 off my site regardless of the number of visitors, page impressions. I dunno sometime I feel like giving up this whole thing with calculator development but then it serves its purpose so I keep on going
I got whole lot of other stuff on the site, Bond Valuation (0, non 0, and perpetual) , YTM and YTC on bonds, all the interest factors used in present and future values of ordinary annuity, annuity due and growing annuity. And god knows what else.
I used to have an option where I let people submit problems to me, and most of these were college students from US taking business courses. What I learned from the problems they submitted was regardless of how the tutorial on the topic explained the ideas, none of the users were willing to do the calculations for themselves. They wanted someone else to do it for them.
I read on this forum that you are not allowed to answer questions from users that submit home work. But that's what it is. These kids get in to schools somehow, they attend the lectures yet they are dumb founded when asked to solve problems related to the coursework. I spent sometime over at Yahoo Answers under a different screen name, the same story repeats there too. I had one guy sent me an email yesterday that I answered one of his questions, he asked me take his mid terms exam online and he was willing to pay me money for that. Gee I mean online learning is fun I guess
I am college drop out long story from the election days of 1992 but hey I teach myself stuff by exploring topics off forums like this one and from some books I have. For a brief period I attended one of the web based university out of Pakistan but getting an inside view of how they ran the show had me decide to leave instead of waste more time. Funny thing was one of the Tutors from that online university in Pakistan once grabbed PVIFA and PVIF tables off my site and stored it in their university learning system. Some years ago I had a collection of Visual Calculus tools that ran as applets and guess what those from China and other countries like Pakistan simply burned the applets of CDs and mass marketed them. The developer, me, who created the gizmos didn't make a cent and those who had nothing to do with it made the money. I sold off all 26 online applets to an Ausi Industrial Mathematician of huge massive sum of $600
May be if I hang around here for a while and learn some of the new ideas I may go back to drawing board and will churn out some new math software
Enough of the rant. Thanks for visiting my site and for your feedback on my tools.