Understanding Intervals: Intersection and Union

This video tutorial explains how to find the intersection and union of intervals. It begins with an introduction to the concepts and symbols used for intersection and union. The video then demonstrates how to graph intervals on a number line and find their intersection and union through examples. It emphasizes the importance of understanding whether intervals intersect to apply the techniques correctly.

What does the symbol for intersection look like?

• A triangle

• An upside-down U

• A square

• A circle

In the first example, what type of circle is used at the number 2 on the number line?

• No circle

• Half circle

• Open circle

• Closed circle

What is the intersection of the intervals (2, 5) and [3, 7]?

• (3, 7]

• [3, 5)

• (2, 5)

• [2, 7]

How do you determine the union of two intervals?

• By multiplying the intervals

• By finding the overlap

• By subtracting one from the other

• By combining the start and end points

In the second example, what type of circle is used at the number 4 on the number line?

• Closed circle

• Open circle

• No circle

• Half circle

What is the intersection of the intervals [1, 6] and (4, 9)?

• [1, 4)

• (4, 6]

• [4, 9)

• (1, 9]

What is the union of the intervals [1, 6] and (4, 9)?

• [4, 6]

• (1, 9]

• (1, 6]

• [1, 9)

Why is it important for intervals to intersect when using this technique?

• It is not important

• It simplifies calculations

• It ensures the technique works

• It makes the graph look better

What is the intersection of the intervals (-∞, 4) and [2, 7)?

• [2, 4)

• [4, 7)

• (2, 7)

• (-∞, 2)

What is the union of the intervals (-∞, 4) and [2, 7)?

• (-∞, 7)

• (-∞, 4]

• [2, 4)

• (2, 7)