HP Forum Archive 14

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Mathematics on the HP-33s... Message #1 Posted by Mikel on 27 Feb 2004, 2:02 a.m. With complex numbers in RPN mode, it is kind of confusing remembering every time which of the numbers of your stack corresponds to the imaginary part. The algebraic mode shows clearly the two parts (even with a marked "i"). I'm an RPN user (10 years with my hp48gx...I know, it is a luxury that can't be compared...but....)but certainly for operations with complex numbers I'll switch to ALG. These are also other things that I expected from a just released HP calculator: 1) If they handle operations with complex numbers, why I can't see complex numbers as a result of SQRT(-1) or Arcsin(-5)? 2) If the 15c could handle vector and matrix operations, why the 33c lacks of that? I know that you can program 3*3 matrix inverse or determinant at most but labels are really few for 32k, and the variables also. The basic programs that the manual shows uses most of the labels for things that the calculator should have "in-build": linear equation solver, vector operations (dot, cross, polar to rect and rect to polar), simple matrix operations (inverse, determinant) 3) Casio "simpler and cheaper" calculators have matrix and vector capabilities. Of course they are not the RPN realm but they make the job (see casio fx-991ms).

Re: Mathematics on the HP-33s... Message #2 Posted by Georg Bisseling on 27 Feb 2004, 6:15 a.m., in response to message #1 by Mikel Buy a HP 48 G+, it has precisely what you are asking for: RPN with usable complex numbers, no arbitrary restrictions in the number of vars or labels, big screen, decent keyboard...

Re: Mathematics on the HP-33s... Message #3 Posted by Mikel on 27 Feb 2004, 1:05 p.m., in response to message #2 by Georg Bisseling But I can't use my beautiful HP48GX on the NCEES FE test!...they are forcing me to use downgraded calculators.

Re: Mathematics on the HP-33s... Message #4 Posted by Ernie Malaga on 27 Feb 2004, 10:32 a.m., in response to message #1 by Mikel Quote: With complex numbers in RPN mode, it is kind of confusing remembering every time which of the numbers of your stack corresponds to the imaginary part. The algebraic mode shows clearly the two parts (even with a marked "i"). I'm an RPN user (10 years with my hp48gx...I know, it is a luxury that can't be compared...but....)but certainly for operations with complex numbers I'll switch to ALG. Which is which? That's the easy part, actually. A complex number is also an ordered pair, plotted on the X/Y plane, using the X coordinate for the real element and the Y coordinate for the imaginary one. The labels X and Y apply to stack levels as well. That's also the reason why you enter the number as (imaginary) [ENTER] (real). When you're done typing, the imaginary portion ends up in the Y-register, as it should. -Ernie

Re: Mathematics on the HP-33s... Message #5 Posted by Mikel on 27 Feb 2004, 1:12 p.m., in response to message #4 by Ernie Malaga C'mon....doing arithmetic operations with complex numbers gets confusing cause every time you have to press the cmplx key plus the operator...it is easier in ALG even though you have to use parenthesis...in my 48gx it was just a matter of brackets. And what about the rest? memory?, invisible decimal place? (poor key layout) mathematics?...don't get me wrong...I love HPs but just because of the NCEES test I have use it...but that doesn't mean that I'm not going to criticize it...honestly they could have given us a better product for the same price...

Re: Mathematics on the HP-33s... Message #6 Posted by Ernie Malaga on 27 Feb 2004, 2:55 p.m., in response to message #5 by Mikel Quote: C'mon....doing arithmetic operations with complex numbers gets confusing cause every time you have to press the cmplx key plus the operator...it is easier in ALG even though you have to use parenthesis... The problem you have, according to your post is _not_ the above. You wanted to know how to identify the real and the imaginary part, and my reply addressed that issue. That said, the CMPLX key mechanism _is_ bothersome in the extreme. I remember disliking it from the start, when I bought my 32S years and years ago. -Ernie

Re: Mathematics on the HP-33s... Message #7 Posted by anonymous on 3 Mar 2004, 7:19 p.m., in response to message #1 by Mikel Quote: 1) If they handle operations with complex numbers, why I can't see complex numbers as a result of SQRT(-1) or Arcsin(-5)? I am working from memory here, so I may be wrong but Im pretty sure the 33s allows this as follows: In RPN mode: 1 CHS CMPLX SQRT should show -1 in top line (Y/imag) and 0 on bottom line (X/real) In ALG mode this would have to be done as ( 1 CHS + 0 CMPLX ) SQRT to force the use of the complex version of SQRT, but should still give a result of "REAL=0, IMAG=1"

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