- A26
- B27
- C25
- D28
View written solutionFree
Correct answer: B
-
Let We need to find
-
First simplify the inner determinant.
For a matrix:
- for an matrix, so for ,
Since ,
Hence,
Also,
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Now compute
So,
Prime factorize:
-
Now use the adjoint determinant formula again.
Let Then
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Now multiply by the outer scalar .
Since is also a matrix,
Therefore,
-
Compare with We get
Hence,
-
So the derived answer is
-
Comparison with stored answer:
- Stored correct answer: B = 27
- Derived answer: 23
Therefore, I do not agree with the stored answer.
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Quick verification by an alternative compact method:
So, Then, (for a matrix), hence Therefore,
This reveals an important correction: the previous step using only determinant properties missed the fact that the matrix itself simplifies to , and scaling occurs before determinant evaluation.
Thus actually, so
-
Final correct answer: which matches option B.
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