The Museum of HP Calculators

# Kelvin Functions for the HP-65

This program is Copyright © 1974 by Hewlett-Packard and is used here by permission. This program was originally published in the HP-65 Math Pac 2.

This program is supplied without representation or warranty of any kind. Hewlett-Packard Company and The Museum of HP Calculators therefore assume no responsibility and shall have no liability, consequential or otherwise, of any kind arising from the use of this program material or any part thereof.

 Kelvin Functions Label Key A B C D E

## Overview

(.25x2)2     (.25x2)4
ber(x) = 1 -  ---------- + --------- - . . .
(2!)2        (4!)2

(.25x2)3     (.25x2)5
bei(x) = .25x2 - ---------- + ---------- - . . .
(3!)2        (5!)2

This program computes successive partial sums of the series. The program stops and displays the last partial sum as the answer, when two consecutive partial sums are equal or more than 50 terms have been added.

Notes:
1. When x is too large, computing a new term of the series might cause an overflow, in that case, display shows all 9's and the program stops.

2. ber (-x) = ber (x), bei (-x) = bei (x)

## Instructions

 Step Instructions Input Data/Units Keys Output Data/Units 1 Enter Program 2 For ber(x) 0 ENTER 3 x A ber(x) 4 For bei(x) 1 ENTER 5 x A bei(x)

## Examples

1. ber (4.4) = -3.93
2. bei (0.6) = 0.09

CODE  KEYS
23  LBL
11  A
41  ENTER
71  x
41  ENTER
71  x
33 03  STO 3
35 00  g LST X
04  4
81  ÷
35 08  g roll dn
44  CLX
33 02  STO 2
35 07  g x<>y
33 01  STO 1
35 23  g x=y
01  1
35 08  g roll dn
35 09  g roll up
33 05  STO 5

23  LBL
01  1
41  ENTER
33 04  STO 4
34 05  RCL 5
61  +
35 23  g x=y
24  RTN
24  RTN
43  EEX
02  2
34 02  RCL 2
02  2
61  +
33 02  STO 2
35 24  g x>y
34 04  RCL 4
24  RTN
34 01  RCL 1
61  +
41  ENTER
71  x
35 00  g LST X
51  -
41  ENTER
71  x
08  8
00  0
71  x
05  5
42  CHS
34 03  RCL 3
71  x
35 07  g x<>y
81  ÷
34 05  RCL 5
71  x
33 05  STO 5
34 04  RCL 4
61  +
22  GTO
01  1
35 01  g NOP
35 01  g NOP
35 01  g NOP
35 01  g NOP
35 01  g NOP
35 01  g NOP
35 01  g NOP
35 01  g NOP
35 01  g NOP
35 01  g NOP
35 01  g NOP
35 01  g NOP
35 01  g NOP
35 01  g NOP
35 01  g NOP
35 01  g NOP
35 01  g NOP
35 01  g NOP
35 01  g NOP
35 01  g NOP
35 01  g NOP
35 01  g NOP
35 01  g NOP
35 01  g NOP
35 01  g NOP
35 01  g NOP
35 01  g NOP
35 01  g NOP
35 01  g NOP
35 01  g NOP
35 01  g NOP
35 01  g NOP
35 01  g NOP
35 01  g NOP
35 01  g NOP
35 01  g NOP
35 01  g NOP
35 n1  g NOP

R1  0 or 1
R2  used
R3  x4
R4  used
R5  used
R6
R7
R8
R9  used