HP 39gs Graphing Solving systems of linear equations, Open the Matrix catalog and create a vector

To divide by a square matrix

To invert a matrix

To negate each element

M1

2

For division of a matrix or a vector by a square matrix, the number of rows of the dividend (or the number of elements, if it is a vector) must equal the number of rows in the divisor.

This operation is not a mathematical division: it is a left- multiplication by the inverse of the divisor. M1/M2 is equivalent to M2–1* M1.

To divide the two matrices M1 and M2 that you created for the previous example, press the following keys:

M1

M2

You can invert a square matrix in HOME by typing the

matrix (or its variable name) and pressing x–1

. Or you can use the matrix INVERSE command. Enter INVERSE(matrixname) in HOME and press

.

You can change the sign of each element in a matrix by

pressing before the matrix name.

Solving systems of linear equations

Example	Solve the following linear system:
	2x + 3y + 4z	= 5
	x + y – z	=	7
	4x – y + 2z	=	1

1.Open the Matrix catalog and create a vector.

MATRIX

15-8 Matrices