Understanding Interval Notation in Algebra I

Interval notation is a cool and easy way to show the domain and range of functions in 9th-grade Algebra I! Let’s explore how this handy tool can help you share math ideas clearly!

What Are Domain and Range?

• Domain: This is all the possible input values (x-values) that a function can take.
• Range: This represents all the output values (y-values) that a function can give.

Why Use Interval Notation?

Interval notation is a quick way to describe these sets! Instead of writing long and complicated sentences, you can use intervals to show all the values simply and quickly!

How Does It Work?

1. Open and Closed Intervals:

   • Open Interval: This type doesn’t include its endpoints and is shown with parentheses. For example, the interval (2, 5) means all numbers that are greater than 2 and less than 5.
   • Closed Interval: This interval includes its endpoints and is shown with brackets. For example, the interval [2, 5] includes both 2 and 5.

2. Combining Intervals: You can also mix different intervals! For example, the domain (-∞, -1] ∪ [1, ∞) shows all numbers that are less than or equal to -1 and all numbers that are greater than or equal to 1!

In Summary:

Interval notation makes it easier to show domains and ranges. This helps you explain math ideas and solve problems with more confidence. So, let’s take advantage of interval notation and boost your math skills!