The relation described by this equation is the set of all ordered pairs where the square of the first thing is the same as the square of the second thing. It's a square pair. If it teamed up with a popular children's cartoon from the '80s, it could do a Square Pair Care Bears Stare. Sorry, we had to share. It turns out x and y can be positive or negative integers, irrational numbers, fractions...any sort of number out there, really. This relation is massive. Like, larger than our knowledge of useless '80s pop culture trivia. {(1, 1), (-1, 1), (1, -1), (-1, -1), . . . } If we want a more manageable relation, which we do, we need to specify which pairs we want. | |