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If A=({:(-2,2),(2,-2):}), then which one...

If `A=({:(-2,2),(2,-2):})`, then which one of the following is correct ?

A

`A^(2)=-2A`

B

`A^(2)=-4A`

C

`A^(2)=-3A`

D

`A^(2)=4A`

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The correct Answer is:
To solve the problem, we need to find \( A^2 \) for the matrix \( A = \begin{pmatrix} -2 & 2 \\ 2 & -2 \end{pmatrix} \) and compare it with \( -4A \) to determine which option is correct. ### Step 1: Calculate \( A^2 \) We start by calculating \( A^2 \) which is \( A \times A \). \[ A^2 = \begin{pmatrix} -2 & 2 \\ 2 & -2 \end{pmatrix} \times \begin{pmatrix} -2 & 2 \\ 2 & -2 \end{pmatrix} \] Using the matrix multiplication formula, we calculate each element of the resulting matrix: - The element at position (1,1): \[ (-2) \times (-2) + (2) \times (2) = 4 + 4 = 8 \] - The element at position (1,2): \[ (-2) \times (2) + (2) \times (-2) = -4 - 4 = -8 \] - The element at position (2,1): \[ (2) \times (-2) + (-2) \times (2) = -4 - 4 = -8 \] - The element at position (2,2): \[ (2) \times (2) + (-2) \times (-2) = 4 + 4 = 8 \] Thus, we have: \[ A^2 = \begin{pmatrix} 8 & -8 \\ -8 & 8 \end{pmatrix} \] ### Step 2: Calculate \( -4A \) Next, we calculate \( -4A \): \[ -4A = -4 \times \begin{pmatrix} -2 & 2 \\ 2 & -2 \end{pmatrix} = \begin{pmatrix} 8 & -8 \\ -8 & 8 \end{pmatrix} \] ### Step 3: Compare \( A^2 \) and \( -4A \) Now we compare \( A^2 \) and \( -4A \): \[ A^2 = \begin{pmatrix} 8 & -8 \\ -8 & 8 \end{pmatrix} \] \[ -4A = \begin{pmatrix} 8 & -8 \\ -8 & 8 \end{pmatrix} \] Since \( A^2 = -4A \), we conclude that this relationship holds true. ### Conclusion Thus, the correct option is **B**, as \( A^2 = -4A \). ---

To solve the problem, we need to find \( A^2 \) for the matrix \( A = \begin{pmatrix} -2 & 2 \\ 2 & -2 \end{pmatrix} \) and compare it with \( -4A \) to determine which option is correct. ### Step 1: Calculate \( A^2 \) We start by calculating \( A^2 \) which is \( A \times A \). \[ A^2 = \begin{pmatrix} -2 & 2 \\ 2 & -2 \end{pmatrix} \times \begin{pmatrix} -2 & 2 \\ 2 & -2 \end{pmatrix} ...
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NDA PREVIOUS YEARS-MATRICES & DETERMINANTS-MQS
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