A formula for IRR

[akmon]

(05-19-2015 08:58 AM)salvomic Wrote:  

(05-18-2015 10:30 PM)Alfon Wrote:  I found this page about IRR-- maybe helps?
http://www.thecalculatorstore.com/epages...D=25612040

I'm seeing it, Alfon, but the formula in there seems to me a bit ...short :-), however I'll try it, this evening.
± is the same as Cyrille, akmon and me are discussion here...

(05-18-2015 11:07 PM)akmon Wrote:  A prettier input:

Code:

EXPORT TIR()
BEGIN
sto(EDITLIST(L1,"TASA INTERNA DE RETORNO"),L1);
SOLVE(ΣLIST(MAKELIST((L1(I)/X^(I-1)),I,1,SIZE(L1))),X)-1;
END;

I'll try it this evening too.
Do you already tested it also with 11 items list?
Our two problem are: solve (or fsolve) that work always in Home and CAS; editing list and create it if not exist (I'd use flows for this purpose)...

Could SOLVE resolve the issue of fsolve() (works well only in CAS)?

EDIT: for now I'm trying (as Cyrille suggests) with solve() and not fsolve() and it works better also with the "11 element list" (2 results, but the first, the negative one has -1 added...), however in CAS Terminal gives the message "Warning, argument is not an equation, solving ...", in Home no message.
Better, however!


Salvo

Yes, I tested with 11, 17, 19 and even 31 flows. It works flawless. It works on Home or CAS mode.
Anyway it´s strange that on emulator the program give [2 results] and on my phisical calculator only one, the right one. The code is exactly the same and Home and CAS settings are exactly the same. How strange.