Problem: The number of points with positive rational coordinates selected from the set of points in the -plane such that , is:
Answer Choices:
A.
B.
C.
D.
E.
Solution:
Since ; for any rational value of and, hence, is rational.
or
Consider the graph of ; it is the half-plane below the line , including the line . Since this half-plane contains an infinite set of rational points (points with rational coordinates), choice ( ) is the correct one.
