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 x_i 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 x_i 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