Consider the equation x^2+(y-2)^2 and the relation “(x, y) R (0,
2)”, where R is read as “has distance 1 of”. For example, “(0, 3) R
(0, 2)”, that is, “(0, 3) has distance 1 of (0, 2)”. This relation
can also be read as “(x, y) belongs to the circle of radius 1 with
center (0, 2)”. In other words: “(x, y) satisfies this equation if,
and only if, (x, y) R (0, 2)”. Does this equation determine a...