HP 39g Graphing Calculator - Manual (Page 175)

Matrices
12
Introduction
You can perform matrix calculations in HOME and in
programs. The matrix and each row of a matrix appear in
brackets, and the elements and rows are separated by commas.
For example, the following matrix:
1 2 3
4 5
6
is displayed in the history as:
[[1,2,3],[4,5,6]]
(If the Decimal Mark in MODES is set to Comma, then the
row separators are periods.)
You can enter matrices directly in the command line, or create
them in the matrix editor.
Vectors
Matrices
Matrix Variables
Vectors are one-dimensional arrays. They are composed of
just one row. A vector is represented with single brackets; for
example, [1,2,3]. A vector can be a real number vector or a
complex number vector, for example [(1,2), (7,3)].
Matrices are two-dimensional arrays. They are composed of
more than one row and more than one column. Two-
dimensional matrices are represented with nested brackets;
for example, [[1,2,3],[4,5,6]]. You can create complex
matrices, for example, [[(1,2), (3,4)], [(4,5), (6,7)]].
There are ten matrix variables available, named MO to M9.
You can use them in calculations in HOME or in a program.
You can retrieve the matrix names from the VARS menu, or
just type their names from the keyboard.
Matrices 12-1