HP 15C Programming Tutorial Posted - 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 15C Programming Tutorial Posted (/thread-206753.html) HP 15C Programming Tutorial Posted - Eddie W. Shore - 12-11-2011 The latest installment: Part 14 (Complex Numbers) Re: HP 15C Programming Tutorial Posted - Geir Isene - 12-11-2011 Now that's a good and useful blog right there. Thanks. Re: HP 15C Programming Tutorial Posted - Thomas Klemm - 12-14-2011 The comparison of the two methods to enter complex numbers confused me slightly because in the first example you start with a stack [x y z t], enter a and b and end up with [a+ib x y y], while in the second example you start with [y z t ?]. Why? I'd start with [x y z t] as well and end up with [a+ib x y z] instead. As I always considered the stack as the interface to communicate with the calculator I don't esteem your solution to solve the quadratic equation much. You can do it without storing any numbers into registers. See message 2 in: Short quadratic solver (HP-15C) To solve your first example you'd just enter the three coefficients of the quadratic equation and run the program: ```2 ENTER 3 I 3 CHS ENTER 4 CHS I 2 Re<>Im E ``` Both solutions are now on the stack. You can use x<>y and (i) to display them. Bonus: the same program can also be used for real coefficients. Kind regards Thomas Edited: 14 Dec 2011, 12:44 p.m.