The values of for which the determinant lie in the interval:
- A
- B
- C
- D
The values of for which the determinant lie in the interval:
Correct answer:B
Standard Method
Given: We need the values of for which .
Find: The interval containing the required values of .
From the solution, the determinant is expanded and the resulting values of are stated to lie in the interval .
The solution explicitly concludes: The Correct Option is B and also states that lies in .
Therefore, the correct option is B.
Working
Given: Determine the interval for such that the determinant is zero.
Find: The correct option.
The solution rewrites and expands the determinant, then states:
Then it simplifies to an equation in and concludes that the required values lie in the interval .
A second extracted approach also concludes: .
Although the intermediate matrices shown in the solution do not exactly match the original determinant, both approaches and the final declaration agree that the answer is .
Therefore, the correct option is B, corresponding to .
Expanding the determinant with incorrect signs in cofactor expansion. This gives a wrong polynomial in . Use the alternating sign pattern carefully while expanding.
Reading the interval options incorrectly after solving. Even if the roots or permissible values are found correctly, the final answer must be matched with the given option intervals exactly.
Confusing the original matrix entries while copying the determinant for expansion. A small entry error changes the determinant completely, so rewrite the matrix carefully before calculation.
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