Hi I would be grateful for replies on how to do this Q.

Define a relation R on R^2 (reals squared) by

(x1,y1)R(x2,y2) iff (x1)^2 + (y1)^2 = (x2)^2 + (y2)^2

Prove that R is an equivalence relation. Describe geometrically the equivalence classes.

Thanks