Interval Notation

Interval Notation

Communicating sets of numbers

What is interval notation?

• System that helps communicate sets (regions) of numbers

• A short alternative to using inequalities like <, >,

   $\le,\ge$  

• Uses brackets for included values (closed circle) and parenthesis for non-included values (open circle)

The next slide is a video...

It is trimmed to begin and end at certain times. You do NOT need to go backwards in the video, nor do you have to go past the stopping point. Put simply, watch the portion that plays on the slide!

Multiple Choice

Look at the Graph. Write the inequality in interval notation.

• [-4, -1)

• (-4, -1)

• (-4, -1]

• [-4, -1]

Multiple Choice

Express the following in Interval Notation

-9 < x ≤ -4

• [-9, -4]

• (-9,-4]

• [-9, -4]

• (-9,-4)

Multiple Choice

Look at the picture. Which number line corresponds to [-2, 5]?

• Graph 1

• Graph 2

• Graph 3

• Graph 4

Multiple Choice

Express the following in Interval Notation

-8 ≤ x < 8

• [-8, 8]

• [-8,8)

• (-8, 8]

• (-8, 8)

Multiple Choice

Write the inequality in interval notation. x > -1

• (-∞, -1)

• (-1, ∞]

• (-∞, -1]

• (-1, ∞)

Multiple Choice

What interval notation does the number line graph represent?

• [∞, -5)

• (∞, -5)

• [-5, ∞)

• (-5, ∞)

Multiple Choice

Write the following in interval notation

x ≥ 100

• (0, 100] (Real quick)

• (∞, 100]

• [100, ∞)

• (∞, 100)

Multiple Choice

Write the following solution in interval notation:

z < 20

• ( -∞ , 20 )

• ( 20,∞)

• ( -∞ , 20)

• ( -∞ , 20]

Multiple Choice

Write the following in interval notation

x < 8

• (8, ∞)

• (8, -∞)

• (-∞, 8)

• [-∞, 8]

Multiple Choice

When graphing b< 6 would you use an open or closed circle?

• open
• closed

Multiple Choice

Look at the picture. Select the correct interval notation for the given number line.

• (-∞, -8) U (-4, ∞)

• (-∞, -8] U [-4, ∞)

• (-8, -4)

• [-8, -4]

Multiple Choice

Look at the picture. Which graph best represents the solution set (-∞, -2) U (5, ∞)?

• Graph 1

• Graph 2

• Graph 3

• Graph 4

Multiple Choice

Write the following in interval notation

x > 6 and x ≤ 10

• (-∞, 6) and (10, ∞)

• [6, 10)

• (-∞, 6] and [10, ∞)

• (6, 10]

Multiple Choice

Look at the graph. Write the inequality in interval notation.

• (-2,5)

• (-∞,-2)⋃(5,∞)

• [-2,5]

• (-∞,-2]∪[5,∞)