41C/CV root finders

[Dieter]

(05-28-2015 06:19 AM)Ángel Martin Wrote:  I just tried the Advantage's TVM and the PPC's FI - both flunk.
They are also included in the TVM Module BTW

I remember also the Standard Pac includes a TVM program ("FIN"). Tried it in V41, et voilà – there is a solution: "I=14,44%".

However, HP else seems to rule out certain combinations of the TVM variables. Maybe these are actually those that lead to multiple or no solution(s). This can be checked.

In fact solving such cases (and some others) is not as easy as it is with a continuously increasing or decreasing TVM function. And finding an initial estimate isn't either. For instance, the guess I posted may cause the solver to find a negative root even if there is a positive one. Maybe the best option then is having the user provide an estimate. #-)

Dieter