(42S) Function Table
02-18-2019, 05:04 AM
Post: #1 Eddie W. Shore Senior Member Posts: 1,131 Joined: Dec 2013
(42S) Function Table
The program FTAB uses the function defined in FX, with variable “X” to generate a 2 column matrix of f(X). The matrix is stored in variable MATS. The program ends with MATS in edit mode, so you see all the points generated. Use the soft key [ → ] to view the entries.

Setting up FX

To set up the function FX, the program needs to be in the following format:
Code:
 00 {nnn-Byte Prgm} 01 LBL “FX” 02 MVAR “X” 03 f(X) starts here, use RCL “X” for X … nn-1 RTN nn END

HP 42S Program FTAB
HP 42S, DM 42, Free42
Code:
 00 { 99-Byte Prgm } 01▸LBL "FTAB" 02 "X Start:" 03 PROMPT 04 STO 01 05 "X Step:" 06 PROMPT 07 STO 02 08 "# Steps:" 09 PROMPT 10 STO 03 11 1 12 - 13 1ᴇ3 14 ÷ 15 STO 04 16 RCL 03 17 2 18 DIM "MATF" 19 INDEX "MATF" 20▸LBL 00 21 RCL 01 22 RCL 04 23 IP 24 RCL× 02 25 + 26 STO "X" 27 STOEL 28 J+ 29 XEQ "FX" 30 STOEL 31 J- 32 I+ 33 ISG 04 34 GTO 00 35 EDITN "MATF" 36 .END.

Example

f(x) = x^2 * e^x

FX:
Code:
 00 { 18-Byte Prgm } 01▸LBL "FX" 02 MVAR "X" 03 RCL "X" 04 ENTER 05 X↑2 06 X<>Y 07 E↑X 08 × 09 RTN 10 .END.

Input:
X Start: 0
X Step: 0.5
# Steps: 10

Result Matrix MATS:
Code:
 MATF=    [ 10x2 Matrix ] 1:1=              0.0000 1:2=              0.0000 2:1=              0.1000 2:2=              0.0111 3:1=              0.2000 3:2=              0.0489 4:1=              0.3000 4:2=              0.1215 5:1=              0.4000 5:2=              0.2387 6:1=              0.5000 6:2=              0.4122 7:1=              0.6000 7:2=              0.6560 8:1=              0.7000 8:2=              0.9867 9:1=              0.8000 9:2=              1.4243 10:1=             0.9000 10:2=             1.9923