How can you determine whether a matrix product AB is defined?

To determine whether the matrix product ( AB ) is defined, you need to check the dimensions of the matrices ( A ) and ( B ). Specifically, if matrix ( A ) has dimensions ( m \times n ) and matrix ( B ) has dimensions ( p \times q ), the product ( AB ) is defined if and only if the number of columns in ( A ) (i.e., ( n )) is equal to the number of rows in ( B ) (i.e., ( p )). If this condition is met, the resulting matrix ( AB ) will have dimensions ( m \times q ).