Chapter 2: Problem 5
Express the given inequality in interval notation and sketch a graph of the interval. \(x<-2\)
Short Answer
Expert verified
The inequality is \((-\infty, -2)\); graph: open circle at \(-2\) and shade left.
Step by step solution
01
Understand the Inequality
The given inequality is \(x < -2\), which means that \(x\) includes all real numbers that are less than \(-2\). It does not include \(-2\) itself.
02
Express the Inequality in Interval Notation
To express the inequality \(x < -2\) in interval notation, we need to identify the starting and ending points of the interval. Since \(x\) can be any number less than \(-2\), the interval starts from \(-\infty\) to \(-2\). However, \(-2\) is not included in the interval. In interval notation, this is written as \((-\infty, -2)\).
03
Sketch the Graph of the Interval
To sketch the graph of the interval \((-\infty, -2)\), draw a number line, place a point at \(-2\), and shade the line to the left of \(-2\) to indicate all numbers less than \(-2\). Use an open circle at \(-2\) because \(-2\) is not included in the interval.
Unlock Step-by-Step Solutions & Ace Your Exams!
-
Full Textbook Solutions
Get detailed explanations and key concepts
-
Unlimited Al creation
Al flashcards, explanations, exams and more...
-
Ads-free access
To over 500 millions flashcards
-
Money-back guarantee
We refund you if you fail your exam.
Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Interval Notation
Interval notation is a concise way of representing inequalities or ranges of numbers on a number line. It captures information about which numbers are included or excluded from an interval.
When we express an inequality like \(x < -2\) in interval notation, we are looking for all possible values that satisfy this inequality. In this case, \(x\) includes all numbers less than \(-2\).
Here's how interval notation works:
When we express an inequality like \(x < -2\) in interval notation, we are looking for all possible values that satisfy this inequality. In this case, \(x\) includes all numbers less than \(-2\).
Here's how interval notation works:
- Parentheses \((\ , \ )\) indicate that the endpoint is not included. This is called open interval.
- Brackets \([\ , \ ]\) indicate that the endpoint is included. This is a closed interval.
- An interval can also be a mix of parentheses and brackets if one end is included and the other is not.
- The symbol \(-\infty\) is always paired with a parenthesis because infinity is not a specific number; it's a concept indicating boundlessness and can't be included, thus always used as \(( -\infty, a )\) or \(( a, \infty )\).
Number Line
A number line is a straight line where each point corresponds to a real number. It is an essential tool for visualizing mathematical concepts, such as inequalities and intervals.
To understand \(x < -2\) on a number line, imagine a straight horizontal line where 0 is usually placed in the center. Negative numbers (-1, -2, -3, ...) extend to the left, and positive numbers (1, 2, 3, ...) extend to the right.
Construction of a number line includes:
To understand \(x < -2\) on a number line, imagine a straight horizontal line where 0 is usually placed in the center. Negative numbers (-1, -2, -3, ...) extend to the left, and positive numbers (1, 2, 3, ...) extend to the right.
Construction of a number line includes:
- Choosing an appropriate scale to mark numbers in sequence.
- Placing negative numbers to the left of zero and positive numbers to the right.
- Using circles to indicate whether a number is included in the interval (a filled circle for inclusion, open circle for exclusion).
Graph of Intervals
Graphing intervals on a number line provides a clear visual method for understanding the extent and limitation of a set of numbers. It is especially useful for comprehending which values satisfy a given inequality.
The graph of intervals makes use of a number line, where one highlights or shades regions that represent the interval.
When graphing the interval \( (-\infty, -2) \), follow these steps:
The graph of intervals makes use of a number line, where one highlights or shades regions that represent the interval.
When graphing the interval \( (-\infty, -2) \), follow these steps:
- Start by drawing a horizontal line to represent the number line.
- Locate \(-2\) on the line.
- Place an open circle at \(-2\) to show it is not included in the interval.
- Shade the area towards the left, away from \(-2\), indicating that the interval comprises all numbers less than \(-2\).