|Re: Complex Number Juxtapositions|
Message #2 Posted by Karl Schneider on 18 Oct 2007, 12:20 a.m.,
in response to message #1 by Trent Moseley
Hi, Trent --
Regarding operations with complex numbers on the HP-35s:
"So near yet so far..."
Formal response: "I concur with your sentiments."
Informal response: "Amen, brother!"
Perhaps more annoying is that SHOW also doesn't work on a complex number, and that there is no simple way to separate the components of a complex number. Thus, the RND limitation can't be circumvented by applying RND to each part separately, but even if RND did operate on a complex number, SHOW won't verify that it worked as intended...
You can ROUND one on the 42s but you can't STORE it.
The second part of that statement is incorrect. A complex number can always be stored to a named variable, or it can be stored to a numbered register if the matrix of storage registers ("REGS") is dimensioned as complex:
RCL "REGS" (a softkey), ENTER, COMPLEX, STO "REGS"
Indeed, RND is applied to both parts of a complex number (in rectangular or polar mode) on the HP-42S. If the user wants to round only one component, the number can first be separated into two reals using COMPLEX.
Try this on an HP-42S: Enter a complex number with 12-digit mantissas for both components (say, pi and e^1), and assemble the number in POLAR mode using COMPLEX. SHOW will then display both components with their 12-digit mantissas. Then, do FIX 03, RND, and SHOW. You'll see 3.142 at angle 2.718 before and after SHOW. Change to RECT mode, and SHOW again. You'll see 12-digit rectangular-coordinate values for both components, indicating that RND was properly applied to the displayed value, even though the number may have been internally represented in rectangular form all along.
Edited: 18 Oct 2007, 12:26 a.m.