Let the set A be defined as A = {a, b, c, d}, and let the relations R and S on the set A be defined as
R = {(d, a), (a, b), (b, c), (b, d) }, and S = {(a, a), (b, d), (d, c)}.
Explain, using the definition of composition of relations on a set why the ordered pair (b, d) is or is not an element of the composition of relations R and S (denoted S o R).