Matrices Unit
A Matrix is a set of numbers arranged in rows and columns so as to form a rectangular array.  The numbers are called the elements, or entries, of the matrix.  Matrices have wide applications in engineering, physics, economics, and statistics as well as in various branches of mathematics. 

The term matrix was introduced by the 19th-century English mathematician James Sylvester, but it was his friend, British mathematician Arthur Cayley, who developed the algebraic aspect of matrices in two papers in the 1850's.
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James Sylvester (1814 - 1897)
Cayley first applied matrices to the study of systems of linear equations, where they are still very useful.  Matrices have also come to have important applications in computer graphics, where they have been used to represent rotations and other transformations of images.
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Arthur Cayley (1821 - 1895)
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