Question

Let R be a relation on the set A={2,4,7,9}. If (2,4) is in R, what must be an element of R for R to be symmetric?

Answer 1

To make R symmetric, (4, 2) must be in R.

Step-by-step explanation:

To determine what must be an element of R for R to be symmetric, we need to understand the definition of symmetric relations. A relation R on a set A is symmetric if for every pair (a, b) in R, the pair (b, a) is also in R. In this case, we are given that (2, 4) is in R, so to make R symmetric, we need to ensure that (4, 2) is also in R.