The determinant of the matrix [ 6 -8 1 1 ] [ 0 2 4 6 ] [ 0 0 4 8 ] [ 0 0 0 -1 ] A. 11 B. -48 C. 0 D. -24

GATE 1997 · Engineering Mathematics · Determinant · medium

Answer: det = -48, so the answer is B. -48

1. Identify the matrix type: The given matrix is upper triangular (zeros below the diagonal). The diagonal entries are 6, 2, 4, -1.
2. Compute the product of diagonal entries: det = 6 * 2 * 4 * (-1) = 12 * 4 * (-1) = 48 * (-1) = -48.