GATE 2021 IN – Question 35
The determinant of $M=\begin{bmatrix}1&2&0&0\\3&4&0&0\\0&0&4&3\\0&0&2&1\end{bmatrix}$ is ______.
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Show answer and explanation
Correct answer: 4 to 4
Explanation
The determinant is the product of its two 2×2 block determinants. The first is 1·4−2·3=−2 and the second 4·1−3·2=−2.
Thus det M=(−2)(−2)=**4**.