HP-15C Owner's Handbook - Pages 138-140 - Solve a system of linear equations - General version - up to 8 equations each with 8 coefficients and 1 constant

Description

N GSB 1 where N is the number of equations (8 or less).

A N N is displayed.
Matrix [A] has a dimension of NxN.

Enter the coefficients of xi where i has values from 1 to N
Press R/S after each is entered.

B N 1 is displayed.
Matrix [B] has a dimension of Nx1.

Enter the constants.
Press R/S after each is entered.

C N 1 is displayed.
Matrix [C] has a dimension of Nx1.

Values for xi are read out in turn by pressing R/S.

64 elements are allowed using a standard HP15C so [A] should in principle be no greater than 7x7. [B] and [C] would then each be 7x1 for a total of 63 elements. In practice, because the program occupies some memory space, only 6 equations can be solved with a standard HP15c. In this case a 6x6, and two 6x1 matrices are required, while leaving some space for the program.

The simulator seems to be able to solve 8 equations, each with 8 coefficients and 1 constant. Including the 8x1 result matrix [C], this is 80 matrix elements in memory. This works for the expanded-memory modes of both the Simulator and the DM15L.

John Patterson
jepattersonatactrix.co.nz
http://www.jepspectro.com

Program Resources

Labels

Name Description
 C Read the matrix elements in [C]
 1 Run Program
 2 Enter coefficients of x
 3 Enter constants
.3 Matrix [C] readout loop

Flags

Number Description
8 gCF8 clear complex number flag

Program

Line Display Key Sequence Line Display Key Sequence
000 019 42;21; 3 f LBL 3
001 42;21; 1 f LBL 1 020 31 R/S
002 43; 5; 8 g CF 8 021 u 44 12 USER STO B
003 42;16; 0 f MATRIX 0 022 22 3 GTO 3
004 36 ENTER 023 3 3
005 42;23;11 f DIM A 024 45;16;12 RCL MATRIX B
006 42;16; 1 f MATRIX 1 025 42 31 f PSE
007 45;16;11 RCL MATRIX A 026 45;16;11 RCL MATRIX A
008 42 31 f PSE 027 42;26;13 f RESULT C
009 42;21; 2 f LBL 2 028 10 ÷
010 31 R/S 029 32 13 GSB C
011 u 44 11 USER STO A 030 43 32 g RTN
012 22 2 GTO 2 031 42;21;13 f LBL C
013 45;23;11 RCL DIM A 032 42;16; 1 f MATRIX 1
014 42;16; 1 f MATRIX 1 033 42;21; .3 f LBL . 3
015 1 1 034 31 R/S
016 42;23;12 f DIM B 035 u 45 13 USER RCL C
017 45;16;12 RCL MATRIX B 036 22 .3 GTO . 3
018 42 31 f PSE 037 22 13 GTO C