The Museum of HP Calculators

HP Forum Archive 14

 42s and 15cMessage #1 Posted by V. Taylor on 3 May 2004, 6:54 p.m. I've seen several statements in this forum and in other places that the 42s and the 15c are very different calcs. I realize that the layout and display is different, but as far as functionality are they really that different? They both do complex numbers, matrices, and programming, right? I still use my 42s on a daily basis but is it worth investing the \$150+ to find out?

 Re: 42s and 15cMessage #2 Posted by Eric Smith on 3 May 2004, 7:34 p.m.,in response to message #1 by V. Taylor The HP-15C does complex numbers, and it does real matrices, but it does not do complex matrices. You can use "tricks" to simulate some operations on complex matrices. See the "HP-15C Advanced Functions Handbook" (available on the Museum CD-ROM) for the details.

 testMessage #3 Posted by Karl Schneider on 4 May 2004, 12:53 a.m.,in response to message #2 by Eric Smith Eric posted, Quote: The HP-15C does complex numbers, and it does real matrices, but it does not do complex matrices. You can use "tricks" to simulate some operations on complex matrices. See the "HP-15C Advanced Functions Handbook" (available on the Museum CD-ROM) for the details. Rarely do I have the inclination to differ with Eric Smith's excellent posts, but here's a minor exception... It's true that the 15C stores only real-valued variables as matrix elements, which requires the user to represent complex-valued matrices as real ones with twice the number of elements. However, the user may perform many of the same matrix calculations for complex-valued matrices, by executing mathematical transformations that are done internally by software that handles complex-valued matrices. The designers of the 15C supported complex-valued matrix operations by providing these necessary transformation utilities (not "tricks") as built-in keyboard functions. The utilities are reasonably intuitive for anyone who is sound in linear algebra; are easy to use; and are documented in the excellent, standard Owner's Handbook as well as in the optional, extra-cost Advanced Functions Handbook. IMO, the built-in utilities for using complex-valued matrices is an excellent example of how HP "went the extra mile" to develop a fully-engineered and functionally-coherent tool for professionals. In that regard, the successor 32S/32Sii and 33S, despite their advantages, don't quite measure up. -- Karl S.

 Re: 42s and 15cMessage #4 Posted by bill platt (les Estats Unis d'Amerique) on 3 May 2004, 7:49 p.m.,in response to message #1 by V. Taylor The 15c has a very small memory compared to the 42s. THe latter is large enough to take any 41CX program (a 41 withyout Zenrom or other super-whizbang aftermarket add-ons). The 15c is a beautiful thing, period. But if you are used to the 42s, I think you will find the 15c a step backwards in time. Every command is on a key. There is no alpha mode. That is part of the beauty. Since I don't have a 42s, I dont't have that problem! :-) regards, Bill

 Re: 42s and 15cMessage #5 Posted by Dano on 3 May 2004, 8:38 p.m.,in response to message #4 by bill platt (les Estats Unis d'Amerique) Ah bill..... I read your insightful posts often. Never would have guessed you don't have a 42s. I like the 15C as a handy, sturdy calculator but when I want to get serious I even skip the 48 and go for my 42s...sorry, one of my two 42s (never saw the need to use them both at the same time ;-)

 Re: 42s and 15cMessage #6 Posted by bill platt on 3 May 2004, 9:29 p.m.,in response to message #5 by Dano Hi Dano! Thanks for your nice note. Well, I would love to have a 42s--but it is hard to get one at a small price! I did miss one for \$102 about a week ago, though. Someday..... Best regards, Bill