Elementary. Matrix Algebra Part

You may recall that in the first chapter we promised that a review of elementary matrix algebra would be forthcoming so the next several chapters will cover this topic all the way from the very basics to the more advanced spectroscopic subjects. 

You may already have discovered that the term matrix is a fanciful name for a table or list. If you have recently made a grocery list you have created an nx 1 matrix, or in more correct nomenclature, an X xl matrix where n is the number of items you would like to buy (rows) and 1 is the number of columns. If you have become a highly sophisticated shopper and have made lists consisting of one column for Store A and a second one for Store B, you have ascended into the world of X x2 matrix. If you include the price of each item and put brackets around the entire column(s) of prices, you will have created a numerical matrix. 

By definition, a numerical matrix is a rectangular array of numbers (termed elements ) enclosed by square brackets [ ]. Matrices can be used to organize information such as size versus cost in a grocery department, or they may be used to simplify the problems associated with systems or groups of linear equations. Later in this chapter we will introduce the operations involved for linear equations (see Table 2-1 for common symbols used). 

The above matrix is a 2 x 2 (rows x columns) matrix. The first number indicates the number of rows, and the second indicates the number of columns. Matrices can be denoted as X2x2 using a capital, boldface letter with the row and column subscript. 

The following illustrations are useful to describe very basic matrix operations. Discussions covering more advanced matrix operations will be included in later chapters, but for now, just review these elementary operations. 

---