InterviewSolution
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If \(\begin{bmatrix} 1 & -3 & 2 \\\ 2 & -8 & 5 \\\ 4 & 2 & λ \end{bmatrix}\) is not an invertible matrix, then what is the value of λ ?1. -12. 03. 14. 2 |
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Answer» Correct Answer - Option 3 : 1 Concept: If the matrix A is not an invertible matrix then | A | = 0 If the matrix A is the non-singular matrix then | A | ≠ 0
Calculations: Given, A = \(\begin{bmatrix} 1 & -3 & 2 \\\ 2 & -8 & 5 \\\ 4 & 2 & λ \end{bmatrix}\)is not an invertible matrix As we know, If the matrix A is non invertible matrix then | A | = 0 ⇒ \(\begin{vmatrix} 1 & -3 & 2 \\\ 2 & -8 & 5 \\\ 4 & 2 & λ \end{vmatrix}\) = 0 ⇒ 1\(\rm (-8\lambda - 10)+3(2\lambda-20)+2(4+32)\) = 0 ⇒ \(\rm -8\lambda - 10+6\lambda-60+72 = 0\) ⇒\(\rm -2\lambda +2 = 0\) ⇒\(\rm \lambda = 1\) Hence, If \(\begin{bmatrix} 1 & -3 & 2 \\\ 2 & -8 & 5 \\\ 4 & 2 & λ \end{bmatrix}\) is not an invertible matrix, then the value of λ is 1. |
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