Let A and B be two non zero square matrices and AB and BA both are defined. It means
Answer & explanation
Correct answer: option 3
AB and BA both are defined
AB → No. of columns of A = No. of rows of B
BA → No. of columns of B = No. of rows of A
So order (A) = m × n
order (B) = p × q
⇒ n = p and q = m
order (A) = m × n
order (B) = n × m
but as they are square matrices
n = m ⇒ both have same order