Chapter 1: Problem 54
Express the inequality interval notation, and then graph the corresponding interval. $$1 \leq x \leq 2$$
Short Answer
Expert verified
The interval notation is \([1, 2]\) and it includes closed endpoints at 1 and 2.
Step by step solution
01
Identify the Inequality
The given inequality is \(1 \leq x \leq 2\), which states that \(x\) is greater than or equal to 1 and less than or equal to 2.
02
Convert to Interval Notation
For an inequality of the form \(a \leq x \leq b\), the interval notation is \([a, b]\). Therefore, the inequality \(1 \leq x \leq 2\) can be expressed as \([1, 2]\).
03
Graph the Interval
To graph the interval \([1, 2]\), draw a number line. Mark and place a closed circle at 1 and another closed circle at 2, indicating that both endpoints are included. Shade the region on the number line between the two circles inclusive of the endpoints.
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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 way to represent a set of numbers within a certain range. It simplifies the expression of inequalities by using brackets and commas. For example, an interval of numbers between 1 and 2, inclusive of both 1 and 2, is written as \([1, 2]\). In this notation:
- The square bracket \([\) indicates inclusion of the endpoint.
- The parentheses \(()\) would indicate exclusion, but they are not used here since the endpoints are included.
- A comma separates the lower and upper bounds of the interval.
Graphing Intervals
Graphing intervals involves representing interval notation visually on a number line. This visual representation can make it easier to understand the range and endpoints of the interval. When graphing an interval like \([1, 2]\):
- Draw a straight horizontal line, which will serve as your number line.
- Identify the points you need: in this case, 1 and 2.
- Place a closed circle on the number line at both 1 and 2 since these numbers are included in the interval.
- Shade the area between the circles, indicating that all numbers from 1 to 2 are part of the solution set.
Closed Interval
A closed interval is a set of numbers where both endpoints are included in the interval. In interval notation, closed intervals are denoted with square brackets like \([a, b]\). This means every point between and including \(a\) and \(b\) is part of the interval.
- A closed interval means every value, starting from the lower bound to the upper bound, is included.
- The usage of closed circles on a number line indicates the inclusion of the endpoints.
- Closed intervals are handy in defining sets that have definite limits.
Number Line
A number line is a visual tool used in mathematics to represent numbers in a linear format. It helps in understanding the concept of intervals, inequalities, and even basic arithmetic operations. Components of a number line include:
- A straight horizontal line which is usually divided into equal parts for whole numbers or integers.
- Points or markers which show specific numbers;
- Certain segments getting highlighted or marked to denote ranges or intervals.