Let R={(P,Q) | P and Q are at the same distance from the origin} be a relation, then the equivalence class of (1,−1) is the set :
Show that the relation R in the set A of points in a plane given by R = {(P, Q): Distance of the point P from the origin is same as the distance of the point Q from the origin}, is an equivalence relation. Further, show that the set of all point related to a point P≠(0,0) is the circle passing through P with the origin as centre.