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Points A(-4,1), B(-1,4) and C(-1,1) are the vertices of triangle ABC. What will be the coordinates of the image of point A if triangle ABC is rotated 90 degrees clockwise about the origin?

 Feb 10, 2019
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\(\text{one way of doing this is to note that the rotation matrix for a 90 degree clockwise rotation is}\\ R=\begin{pmatrix}0 &1\\-1 &0 \end{pmatrix}\)

 

\(R.(x,y) = (y, -x)\\ \text{and this is simple to apply to your points}\\ \text{for example}\\ (-4,1) \to (1,4)\\ \text{I leave rotating the two other points to you}\)

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 Feb 10, 2019

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