A formula for IRR

[akmon]

(05-18-2015 07:55 PM)salvomic Wrote:  

(05-18-2015 07:51 PM)akmon Wrote:  With this code:

Code:

EXPORT IRR()
BEGIN    
   return fsolve(ΣLIST(MAKELIST((L1(I)/X^(I-1)),I,1,SIZE(L1))),X)-1; //  (Original command line from Akmon)
END;

and your 10 numbers list,
I get 0,13917 in home and CAS mode, directly.

should be 11: {-79000, 14000, 11000, 10000, 10000, 10000, 9100, 9000, 4500, 100000}
I get result only with #CAS version, not with the above code, but I'll try again...

I´ve discovered something interesting.
If the number of flows is par, the program gets the solution with no problem. however if the number of flows is impar it cannot solve. For that reason I can solve the first examples (4, 6 flows) but cannot solve 11, 13, or 9 flows. The question is: why?

EDIT: use solve instead fsolve. It works better, anyway the previous question is still curious.