Question

Domain and range. How would I write the domain and range for this graph. The part that confuses me is the open and closed circles mixed together.

Answer 1

Answer: Domain x = [1, 2) ∪ (2, 4) ∪ (4, 6]

Range y = [1, 3) ∪ (3, 5) ∪ (5, 6]

Explanation:

OPEN DOT means the number is NOT included

CLOSED DOT means the number IS included

Domain is all of the x-values (numbers at the bottom of the graph).

x is from 1 to 6 but does not include 2 or 4.

Interval Notation: [1, 2) ∪ (2, 4) ∪ (4, 6]

• brackets [ ] means the number is included.

• parenthesis ( ) means the number is not included

Range is all of the y-values (numbers on the left side of the graph).

y is from 1 to 6 but does not include 3 or 5.

Interval notation: [1, 3) ∪ (3, 5) ∪ (5, 6]