Find the error in the "proof' of the following "theorem." Let R be a relation on a set A that is symmetric and transitive. Then R is reflexive. Let a elementof A. Take an element b elementof A such that (a, b) elementof R. Because R is symmetric, we also have (b, a) elementof R. Now using the transitive property, we can conclude that (a, a) elementof R because (a, b) elementof R and (b, a) elementof R