Posts: 4,027
Threads: 172
Joined: Aug 2005
Hello;
maybe I'm wrong, but it seems you wanted to address your post to Hewlett-Packard Company itself. In fact, this Museum and particularly this Forum are exclusively private initiative.
Anyway, about the formulas: I know the IRR and about all related financial formulas used in Hewlett-Packard calculators can be found at the HP12C's "Owner's Handbook and Programming Guide", Appendix D, titled "Formulas Used". This manual also refers to other specific publications in particular cases, like Standard Securities Calculation Methods as a reference for Bond calculations.
Hope it helps. But if you still need the formulas, feel free contacting me so I can send you more info.
Best regards.
Posts: 14
Threads: 2
Joined: Jan 1970
I do not know exactly what HP uses, but I have a functional set derived using the 28S algebraic equation solver, if you are interested.
E-mail me if you want me to send them.