5. The Coordinate Plane
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To reflect a point in the x-axis, use the same x-coordinate and take the opposite of the y-coordinate. To reflect a point in the y-axis, use the same y-coordinate and take the opposite of the x-coordinate.
(0,2)
We want to reflect a point in the x-axis and then in the y-axis of a coordinate plane. We need to follow two rules to do this.
| Point | Reflection in the x-axis | Reflection in the y-axis |
|---|---|---|
| ( x, y) | ( x, - y) | ( - x, - y) |
| ( 0, -2) | ( 0, 2) | ( 0, 2) |
As we can see, the reflection of the point is at (0,2). Note that the reflection in the y-axis does not change the coordinates of the point. This is supported by the fact that its x-coordinate is 0, and opposite number to 0 is 0. Let’s plot our point and its reflections on the coordinate plane.
We can see that the point is located at (0,2) after both reflections.