File INV_MTRX.ZIP from The Programmer’s Corner in
Category Financial and Statistics
Solves determinant and inverse of a matrix. TP 4.0+ source included.
File Name File Size Zip Size Zip Type
INV_MTRX.PAS 6199 1772 deflated
MATRICES.PAS 5301 1063 deflated
MATRIX.EXE 14336 8446 deflated
README.TXT 2061 838 deflated

## Contents of the README.TXT file

This is a simple program that solves the determinant and inverse of
square matrices. It was written in Turbo Pascal, and the source code files
are included as INV_MTRX.PAS and MATRICES.PAS. To run the program, simply
type MATRIX at the prompt and follow the instructions. Although this
program accepts real numbers as matrix elements, try to keep the numbers
under three decimal places.

This program can be useful for solving systems of equations. For
example, if you have these equations:

Ax + By = C where A, B, C, D, E, and F are real numbers and
Dx + Ey = F x and y are variables,

then x and y are: (the bars represent determinants)

C B A C
F E D F
x = y =
A B A B
D E D E

Or, if you have these equations:

Ax + By + Cz = D
Ex + Fy + Gz = H
Ix + Jy + Kz = L

then x, y, and z are:

D B C A D C A C D
H F G E H G E G H
L J K I L K I K L
x = y = z =
A B C A B C A B C
E F G E F G E F G
I J K I J K I J K

Notice in the second example, the elements of the determinants in the
denominators correspond to the coefficients in the left side of the equations.
Also, notice how the constants D, H, and L (they're constants because they are
not coefficients of x, y, nor z) are in a column and are positioned
accordingly in the determinants of the numerators. This process can be
applied to four equations with four variables, and so on.

Well, I hope you understood that short lesson in higher mathematics.
I also hope you find this program useful.

Allen Kim, 7/20/91

December 16, 2017