Order of AB and BA

Find the Order of AB and BA

Given:

\[ A = \begin{bmatrix} 2 & 1 & 4 \\ 4 & 1 & 5 \end{bmatrix} \]

\[ B = \begin{bmatrix} 3 & -1 \\ 2 & 2 \\ 1 & 3 \end{bmatrix} \]

Step 1: Determine Order of A and B

\[ A \text{ is of order } 2 \times 3 \]

\[ B \text{ is of order } 3 \times 2 \]

Step 2: Find Order of AB

\[ (2 \times 3)(3 \times 2) \Rightarrow AB \text{ exists and is of order } 2 \times 2 \]

Step 3: Find Order of BA

\[ (3 \times 2)(2 \times 3) \Rightarrow BA \text{ exists and is of order } 3 \times 3 \]

Final Answer:

\[ AB \text{ is of order } 2 \times 2, \quad BA \text{ is of order } 3 \times 3 \]

Conclusion:

Matrix multiplication depends on inner dimensions, and AB and BA generally have different orders.

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