Question

Is it possible to define the matrix AB and BA when :
A has 3 columns and B has 4 columns

Answer 1

AB = $A_{p\times 3}{B}_{q\times 4}$ and $B_{q\times 4}{A}_{p\times 3}$
For AB. B should have three rows i.e, q = 3
For AB. A should have four rows i.e, q = 4