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Mathematics · 2025 · 1 mark
CBSE 2025 · Region 2 · Set 3 · Q20
Assertion (A): A = diag [3, 5, 2] is a scalar matrix of order 3 × 3. Reason (R): If a diagonal matrix has all non-zero elements equal, it is known as…
Assertion (A) : A $\displaystyle =\operatorname{diag}\left[\begin{array}{lll}3 & 5 & 2\end{array}\right]$ is a scalar matrix of order $\displaystyle 3 \times 3$.
Reason (R) : If a diagonal matrix has all non-zero elements equal, it is known as a scalar matrix.
Official answer
(D)
Assertion (A) is false but Reason (R) is true.
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CBSE Class 12 Mathematics past-paper question from the 2025 board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.