A^2=I 1. |A|=0 2. |A|=1 3. |A|=-1 4. |A|= 1 - Vidyadip

Question

$\text{A}^2=\text{I}\Rightarrow$

$|\text{A}|=0$
$|\text{A}|=1$
$|\text{A}|=-1$
$|\text{A}|=\pm1$

✓

Answer

$|\text{A}|=\pm1$

Solution:
Given, $\text{A}^2=\text{I}$
Take determinant both sides,
$|\text{A}^2|=|\text{I}|\Rightarrow|\text{A}^2|=1\Rightarrow|\text{A}|=\pm1$

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