1. For each of the equivalence relations below describe the equivalence classes arising. a) xRy iff floor(x)=floor(y)x,y∈R. b) xRy iff x−y is an integer x,y∈R. c) xRy iff x−y is divisible by 5x,y∈Z. d) Let A be the set of all points in the plane with the origin removed. Let the relation R be defined as (a,b)R(c,d) iff the points (a,b) and (c,d) lie on the same line through the origin.