The product of matrix $P$ and $Q$ is equal to a diagonal matrix. If the order of matrix $Q$ is $3 \times 2$, then order of matrix $P$ is:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → $2 \times 3$ ##
Given that the order of matrix $Q$ is $3 \times 2$. It means Q has 3 row and 2 columns.
For the product PQ to result in a diagonal matrix, P must have the same nusmber of columns and Q’s row.
Since, Q has 3 row, P must have 3 columns.
Therefore, the order of P is $n \times 3$, where n denotes the number of rows in P.
Then, $n=2$ (As diagonal matrix is a square matrix)
Then the order of $P=2 \times 3$.