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Find k, if the following matrices are singular. \(\begin{vmatrix}k-1&2&3\\3&1&2\\1&-2&4\end{vmatrix}\)[(k-1, 2, 3) (3, 1, 2) (1, -2, 4)] |
Answer» Let A = \(\begin{vmatrix}k-1&2&3\\3&1&2\\1&-2&4\end{vmatrix}\) Since A is a singular matrix |A| = 0 ∴\(\begin{vmatrix}k-1&2&3\\3&1&2\\1&-2&4\end{vmatrix}\) ∴ (k – 1)(4 + 4) – 2(12 – 2) + 3 (-6 – 1) = 0 ∴ 8k-8-20-21 =0 ∴ 8k = 49 ∴ k = 49/8 |
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