Which of the following mappings is used for a 270-degree (counterclockwise) rotation? (1 point)

• (2,g) → (-y, -2)
O (2,y) → (-y,a)
◎ (z,y) (- , y)
〇 (z,y)

1 answer

To determine which mapping corresponds to a 270-degree counterclockwise rotation, we can start by noting the effect of such a rotation on the coordinates of a point \((x, y)\).

A 270-degree counterclockwise rotation can also be thought of as a 90-degree clockwise rotation. The transformation for a 90-degree clockwise rotation from \((x, y)\) to \((y, -x)\) applies here.

Thus, from \((x, y)\):

  • For a 270-degree counterclockwise rotation, the mapping becomes \((x, y) \to (y, -x)\).

Now let's analyze the given options to see which one matches this transformation.

  1. (2, g) → (-y, -2): This does not correspond to the rotation as it flips both axes.
  2. (2, y) → (-y, a): This does not match the expected output of \((y, -x)\).
  3. (z, y) → (-y, y): This is incorrect since it does not rearrange the coordinates as needed.
  4. (z, y) → (-y, -x): This would imply a reflection and a rotation, which does not match the 90-degree clockwise transformation.

Looking through the options, none of them exactly match \((y, -x)\). However, it's likely that the closest option or the intended transformation was meant to describe a 270-degree rotation.

If we consider the correct transformation being missed, let’s re-check if any combination reflects an implicit transformation. Although, without additional exact options that match \((y, -x)\), none of these mappings seem to correctly define the 270-degree counterclockwise rotation.

If you have additional context or corrections in provided options, please clarify for an accurate choice.