6. We are required to prove that if a relation R, on a set A, is reflexive, then the relation R-1 is also reflexive.
Since R is reflexive, we know that for all elements x in the set A, the ordered pair (x, x) is in R.
Reversing the elements of the ordered pair we see that the ordered pair (x, x) must also be in R-1.
Thus, if the relation R is reflexive, then the relation R-1 is also reflexive.