Short quadratic solver (HP-15C) Message #1 Posted by Gerson W. Barbosa on 22 May 2007, 7:44 p.m.
Two and a half months ago Allen presented an RPL program and a quadratic formula quite suitable for short programs:
http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/archv017.cgi?read=109539#109539
(scroll past the middle of the thread)
This is a 22-step program based on that formula. It was written then and no further attempt has been made to size-optmize it, so it's still possible someone come up with an even shorter program.
001- LBL E
002- ENTER
003- R^
004- /
005- LSTx
006- R^
007- x<>y
008- 2
009- *
010- /
011- CHS
012- ENTER
013- ENTER
014- x^2
015- R^
016- -
017- SQRT
018- +
019- x<>y
020- LSTx
021- -
022- RTN
Usage:
a ENTER b ENTER c GSB E => x1
x<>y => x2
If flag 8 is set the program will also handle complex roots.
The record for the HP-41 appears to be a 16-step program available in the Software Library. What might be the record for the HP-15C?
Gerson.
P.S.: Of course, on the 33S I prefer to use Mr. Hanson's program available in the link. On my everyday 15C, however, every step counts...
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