Question

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Answer 1

Answer:

Hope It's Helps You!!(':

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Answer 2

Orthogonal matrix has value+1 or -1

Let's find

$\\ \sf\longmapsto A=\left[\begin{array}{cc}\sf cos\alpha &\sf sin\alpha \\ \sf -sin\alpha &\sf cos\alpha\end{array}\right]$

$\\ \sf\longmapsto A=cos\alpha(cos\alpha)-sin\alpha(-sin\alpha)$

$\\ \sf\longmapsto A=cos^2\alpha+sin^2\alpha$

$\\ \sf\longmapsto A=1$

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