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Reflect And Transform

Geometry Level 4

\[A=\frac{1}{9}\begin{bmatrix}-1 & 8 &4\\8 & -1 & 4\\4 & 4 & -7\end{bmatrix}\]

What kind of a transformation of \(\mathbb{R}^3\) does \(A\) represent?

Rotation through an angle \(0<\theta<\pi\) Reflection about a plane Reflection about a line None of the others Orthogonal Projection onto a plane

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by Otto Bretscher

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