**Problem : **
Let set *A* = {1, 2, 3} and set *B* = {4, 5}. What is their Cartesian
product *A*×*B*?

*A*×*B* = {(1, 4),(1, 5),(2, 4),(2, 5),(3, 4),(3, 5)}. This is every
possible ordered pair from which the first element is taken from

*A* and the
second element taken from

*B*.

**Problem : **
What is the Cartesian product of the set of real numbers and itself?

The Cartesian product is every ordered pair in the coordinate plane.

**Problem : **
What is the Cartesian product of the set of positive real numbers with itself?

The Cartesian product is every ordered pair in the first
quadrant of the coordinate plane.

**Problem : **
What is the domain and range of the relation {(2, 4),(4, 8),(8, 16)}?

Domain

*D* = {2, 4, 8}. Range

*R* = {4, 8, 16}.

**Problem : **
What is the domain and range of the relation *y* = ±?

Domain

*D* is real numbers

> 0. Range

*R* is all real numbers.