HP 15C Programming Tutorial Posted

[Eddie W. Shore]

The latest installment: Part 14 (Complex Numbers)

Eddie's Calculator Blog

[Geir Isene]

Now that's a good and useful blog right there. Thanks.

[Thomas Klemm]

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.