What transformation is represented by the rule (x, y)→(x, −y) ?
rotation of 180° about the origin
reflection across the x-axis
rotation of 90° counterclockwise about the origin
reflection across the y-axis
rotation of 180° about the origin
reflection across the x-axis
rotation of 90° counterclockwise about the origin
reflection across the y-axis
1 Answer
Sep 11, 2016
Reflection across the x-axis.
Explanation:
Use
#color(blue)"squared paper"# and plot some coordinate points.For example.
:
#(2,3)" and " (-3,-2)" and reflect them in the x-axis."# You should obtain the following results.
#(2,-3)" and " (-3,2)" respectively"#
Note that the x-coordinate remains unchanged, while the y-coordinate is the negative of the original point.
In general this can be expressed as
Under reflection in the x-axis
#(x,y)to(x,-y)#