Question

The domain of the following relation: R: {(−4, 3), (3, 6), (−2, 1), (3, 6)} is

{1, 3, 6}

{−4, 3, −2, 3}

{−4, −2, 3}

No domain exists

Answer 1

domain is first numbers

Answer 2

A binary relation is a set of ordered pairs. Keyword being set. How can a set have two identical entries (3, 6), (3, 6). I'm a little confused about this one.