If \[A=\left( \begin{matrix} 2 & -1 \\ -1 & 2 \\ \end{matrix} \right)\]and I is the unit matrix of order 2, then \[{{A}^{2}}\] equals [Kerala (Engg.) 2002]

If \[A=\left( \begin{matrix} 2 & -1 \\ -1 & 2 \\ \end{ma

1.	If \[A=\left( \begin{matrix} 2 & -1 \\ -1 & 2 \\ \end{matrix} \right)\]and I is the unit matrix of order 2, then \[{{A}^{2}}\] equals [Kerala (Engg.) 2002]
A.	\[4A-3I\]
B.	\[3A-AI\]
C.	\[A-I\]
D.	\[A+I\]
Answer» B. \[3A-AI\]

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If \[A=\left( \begin{matrix} 2 & -1 \\ -1 & 2 \\ \end{matrix} \right)\]and I is the unit matrix of order 2, then \[{{A}^{2}}\] equals [Kerala (Engg.) 2002]

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