Question

What happens to the sign or signs of the coordinates when you reflect a point?

Answer 1

Part a: Reflecting a point across the x-axis, changes the sign of the y-coordinate.

Part b: Reflecting a point across the y-axis, changes the sign of the x-coordinate.

Part c: Reflecting a point across both the axes, changes the signs of both the coordinates.

Explanation:

Part a: Reflecting a point across the x-axis

The reflection is a transformation of a figure which represents a flip.

The rule for a reflection over the x -axis is given by

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

Hence, this represents the change of sign of the y-coordinate.

Thus, Reflecting a point across the x-axis, changes the sign of the y-coordinate.

Part b: Reflecting a point across the y-axis

The rule for a reflection over the y -axis is given by

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

Hence, this represents the change of sign of the x-coordinate.

Thus, Reflecting a point across the y-axis, changes the sign of the x-coordinate.

Part c: Reflecting a point across both the axes

The rule for a reflection across both the axes is given by

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

Hence, this represents the changes the signs of both the coordinates.

Thus, Reflecting a point across both the axes, changes the signs of both the coordinates.