HP-15C using integration in a program
05-06-2022, 06:58 AM (This post was last modified: 05-06-2022 12:19 PM by edwinst.)
Post: #1
 edwinst Junior Member Posts: 2 Joined: May 2022
HP-15C using integration in a program
Dear forum members!

[UPDATE: Sorry, it was a stupid pilot error. The calculator stores the program instruction only after the label of the function to be integrated has been keyed in. For some reason I expected the command to show up immediately but of course it does not, consistent with other commands using a label.]

The HP-15C manual states that numerical integration can be used as an instruction in a program. (p. 203 for the HP15-C LE Owner's Handbook, "Using [INTEGRATE] in a Program").

However, when I try to key in INTEGRATE in program mode, my calculators just ignore it. I tried it on an original HP-15C and on the HP-15C LE with the same result.

Does anyone know whether using integration from a program is actually possible, and if so, how?

best regards

Edwin
05-07-2022, 06:58 AM
Post: #2
 rawi Member Posts: 178 Joined: Nov 2019
RE: HP-15C using integration in a program
Hi Edwin,

its not complicated and can best explained by a small example.

Assume you want to write a program that integrates the function y=x^2. Lower limit is in the y register, upper limit in the x register.

Your main program is LBL A. And you need a second program with the function to integrate. Assume this is LBL B.

LBL A // 001 - 42,21,11
f (S) B // 002 - 42,20,12 (S) stands for Integral sign above the multiplication key
g RTN // 003 - 43 32
LBL B // 004 - 42,21,12
g x² // 005 - 43 11
g RTN // 006 - 43 32

Example:
To get the integral from 0 to 2 of y=x²:
0 ENTER 2 fA --> 2,667 which is correct
05-07-2022, 07:27 AM
Post: #3
 edwinst Junior Member Posts: 2 Joined: May 2022
RE: HP-15C using integration in a program
Hi rawi,

(05-07-2022 06:58 AM)rawi Wrote:  its not complicated and can best explained by a small example.

Thanks for the nice example! Yes, it works fine and I was just being dumb and did not realize that the integrate command would only show up after I had keyed in the label of the function to integrate. I have since updated my post to that effect.

best regards

Edwin
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