Question

Rotate the point (-9,1) around the origin 90 degrees CW.(y, -x) State the image of the point.

Answer 1

We have that the general rule for a 90 degrees rotation about the origin, counterclockwise, is:

$R_{90}(x,y)=(-y,x)$

In this case we have the point (-9,1), then, applying the rotation we have the following:

$R_{90}(-9,1)=(-1,-9)$

we can see the rotation on the following plane: