What are some sample matrix multiplication problems?

1 Answer
Topscooter
Dec 24, 2015

It doesn't commute, or is not always defined.

Explanation:

The product of two square matrices (a square matrix is a matrix that has the same number of rows and columns) #AB# is not always equal to #BA#. Try it with #A = ((0,1),(0,0))# and #B =((0,0),(0,1))#.

In order to calculate the product of two rectangular matrices #C# and #D#, if you want #CD# you need #C# to have the same number of columns as the number of rows of #D#. If you want #DC# it's the same problem with the number of columns of #D# and the number of lines of #C#.

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