If A =
then det(A-1) is _____________ (correct to two decimal places).
Correct Answer :
Solution :
The correct answer is 0.25.
To find the determinant of the inverse matrix, we use the property of determinants for invertible matrices, which states that:
From the given image, the matrix is:
Notice that matrix is an upper triangular matrix (all entries below the main diagonal are zero). The determinant of any triangular matrix is simply the product of its diagonal elements:
Alternatively, we can compute the determinant by expanding along the first column:
Now, using the relationship between the determinant of a matrix and its inverse:
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