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Find the matrix of co-factors for the matrices :\( \begin{bmatrix}1& 3 \\[0.3em]4 & -1 \\[0.3em]\end{bmatrix}\)[1,3,4,-1] |
Answer» Let A = [1,3,4,-1] \( \begin{bmatrix}1& 3 \\[0.3em]4 & -1 \\[0.3em]\end{bmatrix}\) Here, a11 = 1, M11 = -1 ∴ A11 = (-1)1+1(-1) = -1 a12 = 3, M12 = 4 ∴ A12 = (-1)1+2(4) = -4 a21 = 4, M21 = 3 ∴ A21 = (-1)2+1(3) = -3 a22 = -1, M22 = 1 ∴ A22 = (-1)2+1(1) = 1 ∴ The co-factor matrix = \( \begin{bmatrix}A_{11}& A_{12} \\[0.3em]A_{21} &A_{22} \\[0.3em]\end{bmatrix}\) = \( \begin{pmatrix}-1& -4 \\[0.3em]-3 &1 \\[0.3em]\end{pmatrix}\) |
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