Introduction and Examples
DEFINITION: A matrix is defined as an ordered rectangular array of numbers. They can be used to represent systems of linear equations, as will be explained below.
Here are a couple of examples of different types of matrices:
Symmetric Diagonal Upper Triangular Lower Triangular Zero Identity
And a fully expanded m×n matrix A, would look like this:
... or in a more compact form:
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Matrix Addition and Subtraction
DEFINITION: Two matrices A and B can be added or subtracted if and only if their dimensions are the same (i.e. both matrices have the same number of rows and columns. Take:
Addition
If A and B above are matrices of the same type then the sum is found by adding the corresponding elements aij + bij .
Here is an example of adding A and B together.
Subtraction
If A and B are matrices of the same type then the subtraction is found by subtracting the corresponding elements aij − bij.
Here is an example of subtracting matrices.
Now, try adding and subtracting your own matrices.