Chapter 1: Problem 73
Solve the absolute value inequality. Express the answer using interval notation and graph the solution set. $$|x| \leq 4$$
Short Answer
Expert verified
The solution is \([-4, 4]\).
Step by step solution
01
Understanding Absolute Value Inequality
The inequality \(|x| \leq 4\) involves the absolute value of \(x\). This means that \(x\) is at most 4 units away from zero on the number line. The absolute value inequality \(|x| \leq 4\) implies both \(-4 \leq x \) and \(x \leq 4\).
02
Break Down the Absolute Value Inequality
Rewrite the absolute value inequality \(|x| \leq 4\) as a compound inequality: \(-4 \leq x \leq 4\). This shows the range of values that \(x\) can take, satisfying the inequality.
03
Express in Interval Notation
Convert the compound inequality \(-4 \leq x \leq 4\) into interval notation. The solution in interval notation is \([-4, 4]\), which includes all real numbers from -4 to 4, inclusive.
04
Graph the Solution Set
To graph the solution set, draw a number line, and shade the region between -4 and 4. Use closed circles or dots at -4 and 4 to show that these boundary points are included in the solution set, representing the interval \([-4, 4]\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Interval Notation
Interval notation is a mathematical tool used to express a range of values in a compact form. When we deal with inequalities, like \-4 \leq x \leq 4\, interval notation helps us describe all possible values that \(x\) can take, within a defined range, by using brackets.
- Square brackets \([-4, 4]\) indicate that the endpoints -4 and 4 are included in the range. This happens when the inequality symbol is "less than or equal to" or "greater than or equal to."
- Parentheses, on the other hand, suggest that an endpoint is not included, which is common with strict inequalities ("less than" or "greater than", e.g., \(( -4, 4 )\)).
Compound Inequalities
Compound inequalities involve two separate inequalities that are combined into a single statement by the word 'and' or 'or'. For example, the inequality \-4 \leq x \leq 4\ is a compound inequality stating that \(x\) must satisfy both \-4 \leq x\ and \x \leq 4\.
Bringing together multiple inequalities allows us to define a range of values that solves both parts simultaneously:
Bringing together multiple inequalities allows us to define a range of values that solves both parts simultaneously:
- If connected by 'and', the solution must satisfy both inequalities at the same time.
- If linked by 'or', the solution can satisfy either one of the inequalities or both.
Graphing Inequalities
Graphing inequalities visually represents the solution set on a number line. To graph the solution of \(|x| \leq 4\), you need to show all possible values of \(x\) that fit within the range indicated by the inequality.
- Draw a number line.
- Highlight the relevant interval: Shade the number line between -4 and 4, ensuring the entire region is marked to signify all numbers in the interval are solutions.
- Indicate included endpoints by placing closed circles or dots at -4 and 4. This underscores the fact these points are included in the solution set.