Since (x, y) is in R S, it means that there exists an element z in A such that (x, z) is in R and (z, y) is in S.
Since R is symmetric, if (x, z) is in R, then (z, x) is also in R.
Similarly, since S is symmetric, if (z, y) is in S, then (y, z) is also in
Show more…