A reflection across the line y=x can be described by the rule:
[tex](x,y)\longrightarrow(y,x)[/tex]
We can deduce this from the graph:
For example, a point that is (1,3) will have its image at (3,1).
In the case of a reflection across the line y=-x, we have the following graph:
The rule is:
[tex](x,y)\longrightarrow(-y,-x)[/tex]
For example, for the point (1,2), its image will be (-2,-1).
