Answer: AB is defined but BA may not be defined.
- A AB = BA
- B AB and BA are always both defined
- C det(AB) = det(A) + det(B)
- D AB is defined but BA may not be defined
Correct answer: D. AB is defined but BA may not be defined
Explanation: AB is defined when columns of A = rows of B (result is m x p), but BA requires p = m. This is not always satisfied.
Concept context
Evaluation of determinants, cofactors, adjoint, inverse of matrix, Cramer's rule and area applications. Always in board and JEE.