Question

which of the following mappings is used for a 270-degree counterclockwise rotation

(x,y) --> (-x, -y)
(x, y) --> (-y, x)
(x,y) --> (-y, -x)
(x,y) --> (y, -x)

Answer 1

A 270-degree counterclockwise rotation corresponds to moving a point (x, y) to a new position where the x-coordinate becomes the negative of the y-coordinate and the y-coordinate becomes the x-coordinate.

Thus, the mapping for a 270-degree counterclockwise rotation can be represented as:

\[
(x, y) \rightarrow (y, -x)
\]

So, the correct mapping from your options is:

\((x,y) \rightarrow (y, -x)\)