From: Paolo Bonzini Date: 2008-02-09T01:59:55+09:00 Subject: Re: Internal Rate of Return (#156) > I think one point, which isn't brought out here and not well in the > wikipedia article either, is that given all of the C_t, you still have > two unknowns: IRR (which we are attempting to solve for) and NPV. > > In this case, you want NPV set to zero in order to solve for IRR. Or > did I miss something? Yes. At least I get the right answer if the "irr" function solves for NPV=0. :-) Paolo