HP-11C and complex numbers - Printable Version +- HP Forums (https://archived.hpcalc.org/museumforum) +-- Forum: HP Museum Forums (https://archived.hpcalc.org/museumforum/forum-1.html) +--- Forum: Old HP Forum Archives (https://archived.hpcalc.org/museumforum/forum-2.html) +--- Thread: HP-11C and complex numbers (/thread-245633.html) HP-11C and complex numbers - Antlab - 06-27-2013 Hi all. In this period I am exploring the interesting world of the calculator emulators, in particular for my new Android phone. It is fascinating being able to retrace decades of development with the various models. In these days I found a nice HP-11C emulator for Android, and I am trying to discover the main differences respect to the 15C, that I know a bit better. I also downloaded the original manual, but I still have a doubt, concerning the handling of complex numbers. I see that the 11C, as the bigger sister, has the (i) and I functions, (over the COS and TAN keys), but I did not understand their use, because it seems that it doesn't have a Commplex Mode as in the 15C. Could you please clarify this issue? Thanks. Re: HP-11C and complex numbers - Marcus von Cube, Germany - 06-28-2013 The 11C does not do complex arithmetic. I and (i) are used for indirect addressing exclusively. Re: HP-11C and complex numbers - Katie Wasserman - 06-28-2013 Register I is also used for loop control. Re: HP-11C and complex numbers - Thomas Klemm - 06-28-2013 Both ISG and DSE work only with register I. Cheers Thomas Re: HP-11C and complex numbers - Torsten - 06-28-2013 Have a look on the compare features function on this site: HP-11C vs. HP-15C Re: HP-11C and complex numbers - Antlab - 06-28-2013 Thanks to all for the fast answers, now I understand better the differences between the two models concerning complex numbers, and will try to study the question of indirect addressing with (i) and I.