|Re: 12C TVM|
Message #3 Posted by Karl Schneider on 10 Mar 2006, 2:36 a.m.,
in response to message #1 by lary
The odd-period handling looks like a practical, real-world enhancement, designed to handle, in one step, the interest-accruing partial period after which a loan is initiated to the start date of the first regular period. The two examples of loans on pp. 59-61 (as well as my own new-car loan in the 1980's) were set up like this.
The example from the 1977 HP Journal article (JOURNALS\77OCTAC.PDF from CD #6 of the MoHPC CD-ROM set) was for the desktop HP-92, which did not have this partial-period feature. It may have been an enhancement for the HP-12C.
And why didn't the Pioneer-series financial calc's (HP-10B, HP-14B, HP-17B/17BII) retain this feature? Maybe a desire for consistency of algorithm and results between the models. Only the 17B/17BII had the built-in calendar functions (present in the HP-12C and HP-92) for calculating the number-of-days length of the partial period. Without the "delta-days" function, handling the partial period is more of a manual exercise, anyway.
PS: The "C" annunciator that Luiz talked about for this problem represents some cleverness in the Voyager platform, which included five models sharing the same display unit. C stands for "compunding" on the financial HP-12C; "complex mode" on the scientific HP-15C; and "carry bit" on the computer-science HP-16C.
Edited: 10 Mar 2006, 2:42 a.m.