Posted by Yadlay on .
Two matrices can be multiplied only if their sizes are compatible. Suppose that U is an m × n matrix, and that V is a p × q matrix. In order for U•V to make sense, what must be true of the dimensions of these matrices? Although matrix multiplication uses dot products, it is common to write UV without the dot, which will be done from now on.

matrices 
SraJMcGin,
Some of the following sites may help:
http://search.yahoo.com/search?fr=mcafee&p=matrix+tutorials
Sra