Introduction
Matrices
Matrices – rectangular arrays of numbers – are actually useful
for much more than solving linear systems. In this section, we're going to look
at operations you can do on matrices as a whole, instead of just on individual
rows. To begin with, some terminology and examples.
An m x n matrix A
is a rectangular array of numbers with m rows and n columns. The numbers
are called the entries
of A.
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A row matrix is one with
a single row.
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A column
matrix is one with a single column.  |
A square
matrix is one with the same number of rows as columns.
Entries of a square matrix with the same row and column numbers
lie along its main diagonal.
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We're going to look at when and how you can treat matrices as objects you can
add, multiply and so on, and how these calculations compare with ordinary number
calculations.