HP 50g, degree mode, complex polar numbers w/ negative angle Paul Ozog Junior Member Posts: 6 Threads: 3 Joined: Oct 2007 10-20-2008, 11:30 PM If I try to get the (Re, Im) format of: exp(-22.6*i) I get (-.843, .539). Isn't this blatantly wrong? Just think about it. The Re coordinate must be positive, and the Im negative. Note the calc is in degree mode. Am I missing something? This is pissing me off to no avail. Karl Schneider Posting Freak Posts: 1,792 Threads: 62 Joined: Jan 2005 10-21-2008, 01:46 AM Quote: If I try to get the (Re, Im) format of: exp(-22.6*i) I get (-.843, .539). Isn't this blatantly wrong? Paul -- It's wrong, alright. Quote: Just think about it. The Re coordinate must be positive, and the Im negative. Note the calc is in degree mode. Am I missing something? Hmm, polar and degree mode. Maybe you meant, 1.00 / -22.6 degrees? That converts to 0.92321 - i*0.38430 in rectangular mode. However, you specified a complex number in rectangular form. I cannot obtain your result for antilogarithm. I don't have an HP-50g, but I do have practically every other HP calculator with built-in complex-number support. Every one I've tried yields the same answer, in degree or radians mode: e^(-i*22.6) ~= -0.82031 + i*0.57193 I even evaluated your expression as an algebraic expression on the HP-49g and HP-48G, and got the same answer. By Euler's Theorem, ``` eix = (cos x) + i*(sin x) [x in radians] ``` Degrees mode will be ignored by the HP models for complex-number calculations, because exponential (natural antilogarithm) requires a physically dimensionless input. -- KS Edited: 21 Oct 2008, 1:59 a.m. V-PN Posting Freak Posts: 785 Threads: 13 Joined: Jan 2005 10-21-2008, 02:19 AM My 50g functions correctly check your input, please The explanation given by Karl is correct Marcus von Cube, Germany Posting Freak Posts: 3,283 Threads: 104 Joined: Jul 2005 10-21-2008, 02:31 AM On a TI (Voyage 200) you can simply type e^(-22.6°*i) and get the intended result. On the HP however, EXP(-22.6_°*i) cannot be evaluated; it's displayed as e-(22.6*1_°*i) but EVAL or ->NUM fail with the message "Bad Argument Type". You can use the D->R function instead: EXP(D->R(-22.6)*i) works as intended and returns (0.9232,-0.3843) if you press ->NUM. Paul Ozog Junior Member Posts: 6 Threads: 3 Joined: Oct 2007 10-21-2008, 07:48 PM Whoops - forgot that (strictly speaking) Euler takes the angle to be in radians. You can't blame me when I'm surrounded by people typing exp(-22.6*i) in ti calcs, and when my electromagnetics textbook always gives polar-form complex numbers in degrees. Thanks for the help. V-PN Posting Freak Posts: 785 Threads: 13 Joined: Jan 2005 10-22-2008, 02:05 AM This was actually the post that let me to understand the problem at hand - and to give the solution as well :-) « Next Oldest | Next Newest »

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