(12C+) Integration by Trapezoidal Rule

[Gamo]

This program is adapted from the Sinclair Enterprise Mathematics booklet on page 28.4

Program to run Integration of a Function by Trapezoidal Rule Formula.

Example Usage:

7
∫ (X² - 5) dX
1

Start f(x) at line 46 and end with [GTO] 13
Use R0 for each X in the equation

Record Equation: [GTO] 45 [f] [P/R]

[RCL] 0 [RCL] 0 [x] 5 [-] [GTO] 13

[f] [P/R] // Goto Run Mode

To Run: [f] [PRGM] // Set to top of program line 00

1 [R/S] display -1
7 [R/S] display "running" in about 10 second then answer ≈ 84.0240

[f] 0 display answer = 84

Program:

Code:


01 STO 0
02 CHS
03 R/S
04 +
05 EEX
06 3
07 ÷
08 STO 2
09 0
10 STO 3
11 STO 1
12 GTO 46
13 STO 5
14 RCL 1
15 1
16 -
17 0
18 X<>Y
19 X≤Y
20 GTO 37
21 RCL 5
22 RCL 6
23 +
24 2
25 ÷
26 RCL 2
27 x
28 STO+3
29 EEX
30 3
31 RCL 1
32 -
33 0
34 X<>Y
35 X≤Y
36 GTO 44
37 RCL 5
38 STO 6
39 RCL 2
40 STO+0
41 1
42 STO+1
43 GTO 12
44 RCL 3
45 GTO 00
46 f(x)
47
.
.
.
xx GTO 13

Remark:
This program is best use on HP-12C+ or App Emulator.
This program setup the intervals to EEX 3 for best accuracy possible but
for slower HP-12C can be change the intervals lower to EEX 2 with less accuracy.
To change interval is on line 05,06 and 29,30

Gamo 10/2021