Question

If the graph of a relation is symmetric about the line y=x and the point (a,b) is on the graph, then which point must also be on the graph?

Answer 1

is it (b,a)?

Answer 2

Symmetry about the line y = x

For our last symmetry, look back at the black and pink points. In this case the x & y coordinates have been interchanged. That is, (b,c) and (c,b) are symmetric about the line y = x. Much of our later work with this type of symmetry is going to involve functions. In that case we are going to be interested in creating an equation whose graph is symmetric (about y = x) with a given graph. We do so by interchanging the x's and y's

http://www.mesacc.edu/~marfv02121/readings/symmetry/