मराठी

If a = [ 3 4 2 4 ] , B = [ − 2 − 2 0 − 1 ] , Then ( a + B ) − 1 = (A) is a Skew-symmetric Matrix (B) A−1 + B−1 (C) Does Not Exist (D) None of These - Mathematics

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प्रश्न

If \[A = \begin{bmatrix}3 & 4 \\ 2 & 4\end{bmatrix}, B = \begin{bmatrix}- 2 & - 2 \\ 0 & - 1\end{bmatrix},\text{ then }\left( A + B \right)^{- 1} =\]

पर्याय

  • is a skew-symmetric matrix

  • A−1 + B−1

  • does not exist

  • none of these

MCQ
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उत्तर

none of these
We have,

\[\left( A + B \right) = \begin{bmatrix}1 & 2 \\ 2 & 3\end{bmatrix}\]

\[ \therefore \left| A + B \right| = - 1 \neq 0\]

\[\text{ Thus,} \left( A + B \right)^{- 1}\text{ exists }. \]

Now,

\[ \left( A + B \right)^T = \begin{bmatrix}1 & 2 \\ 2 & 3\end{bmatrix}\]

Here,

\[ \left( A + B \right)^T \neq - \left( A + B \right)\]

Hence, it is not a skew symmetric matrix.

\[\text{We also know that } A^{- 1} + B^{- 1}\text{ is not the same as }\left( A + B \right)^{- 1} .\] 

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पाठ 7: Adjoint and Inverse of a Matrix - Exercise 7.4 [पृष्ठ ३७]

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आरडी शर्मा Mathematics [English] Class 12
पाठ 7 Adjoint and Inverse of a Matrix
Exercise 7.4 | Q 3 | पृष्ठ ३७

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