Choose the wrong statement.
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → For every matrix A, AA' + A'A is defined
Let matrix $A$ be of order $m \times n$.
- $AA'$ will be of order $m \times m$
- $A'A$ will be of order $n \times n$
For addition, matrices must have the same order. Since $m \neq n$ in general, $AA' + A'A$ is not always defined.
Hence, Option (3) is incorrect.
- Option (1): True $\to$ $AA'$ and $A'A$ are always square
- Option (2): True $\to$ $AA'$ is always symmetric
- Option (4): True $\to$ If $A$ is square ($n \times n$), both are same order, so addition is defined