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Matrix Trace - Class XII
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QuestionClick to flip
For what value of
k, the matrix $A = \begin{bmatrix} 4 & 3 -k\\ 1 & 2 \end{bmatrix}$ is
not invertible?
AnswerClick to flip back
A
(a)$k = -5,$
💡 Explanation:
A matrix is not invertible if its determinant is zero. Det(A) = (4 * 2) - (1 * (3 - k)) = 8 - 3 + k = 5 + k. Setting 5 + k = 0 gives k = -5.