HP50G Complex Number CAS manipulations

04072015, 06:24 PM
Post: #1




HP50G Complex Number CAS manipulations
In page 22 of the Complex Numbers with the HP49G marathon PDF, the author states:
Quote:Let's suppose, we have the equation The answer given is a long statement of the form sqrt(RE(Z)^4− 2RE(Z)^3+2(IM(Z)^2+1) ...etc) My question is how is he getting the CAS to expand the original equation in this way? The most that happens for me is that I get absolute value symbols "" placed around the z^2  z. I have tried several combinations of CAS settings, but to no avail. Can someone help me with the settings and key sequence? I am using an HP50G. Thanks. 

04072015, 07:03 PM
(This post was last modified: 04072015 07:04 PM by Gerald H.)
Post: #2




RE: HP50G Complex Number CAS manipulations
Are you in complex mode? Is the C annunciator showing or R?
Set complex with HOLD LEFT SHIFT & I. ABS should then work as you want. 

04072015, 07:04 PM
(This post was last modified: 04072015 07:25 PM by Gilles.)
Post: #3




RE: HP50G Complex Number CAS manipulations
Quote:Let's suppose, we have the equation to solve this, I just do : 1/ Verify you are in complex mode (LShift & i to toggle mode if necessary) 2/ 'z^2 − z' 'z' SOLVE For the ABS see flag 128 (variables are only real, or variables can be complex) (but it's unclear for me what does exactly this flag) 

04072015, 07:43 PM
Post: #4




RE: HP50G Complex Number CAS manipulations
Yes, I'm in complex mode, but thanks for the shortcut.
I must be doing something stupid somewhere, as ABS still doesn't expand the expression, and when I do: 'z^2 − z' 'z' SOLVE I just get: {z=0 z=1} I changed flag 128, but no difference. I'm asking this because in that document, the author goes on to list a program that allows numerical solving on complex variables  which sounds very interesting, but it hinges on substituting parts of the expression that is expanded by ABS. Thanks 

04072015, 08:07 PM
(This post was last modified: 04072015 08:19 PM by Gilles.)
Post: #5




RE: HP50G Complex Number CAS manipulations
(04072015 07:43 PM)Hammonds Wrote: I must be doing something stupid somewhere, as ABS still doesn't expand the expression, and when I do: It's the correct answer (for example 'z²=1' 'z' SOLVE returns {z=i , z=i } Quote:I changed flag 128, but no difference. Uncheck flag 128 (Cmplx var allowed) Complex mode Then do 'z^2z=0' ABS and you get the result with RE and IM parts.... Code: 'SQRT(RE(z)^4+(2*IM(z)^2+2)*RE(z)^2+(IM(z)^42*IM(z)^2+1))=0' 

04072015, 08:23 PM
Post: #6




RE: HP50G Complex Number CAS manipulations
It is working now.
Thank you. 

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