Plus42 Equations, Preview Release

[Thomas Okken]

(06-17-2022 10:49 AM)jonmoore Wrote:  The assumption that I would question is that HP is wrong. TVM calculations on the 12C have been proven to be robust by multiple institutions and individuals (within the confines of the calculator's precision).

HP wouldn't continue to sell the 12C 40 years down the line if it had mission-critical errors.

I'd say it's more of a "don't care" kind of thing. The sign change refers to a situation where, after having repaid a loan in full, you keep on paying, and you continue to use the same interest rate on the surplus as on the debt. Since the situation is nonsensical, I assume it doesn't really matter whether you calculate it like the 17B does, or like Plus42. I merely went with the simplest approach, but I'm prepared to reconsider if this approach causes problems in practice.