Difference between revisions of "Interval"

Revision as of 22:11, 16 August 2013

Definition

An interval is a range of values. The most common uses of an interval are for domain and range.

Symbols

If an interval has either $($ or $)$ in it, the values at the end are NOT included in the interval. For example, the interval $x \in (3,5)$ refers to the inequality $3 < x < 5.$

If an interval has either $[$ or $]$ in it, the values at the end ARE included. For example, the interval $x \in [2.5,7]$ refers to the inequality $2.5 \le x \le 7.$

If both endpoints are not included, then the interval is open. If both endpoints are included, then the interval is closed.

Note: The symbols $($ and $)$ are used with $-\infty$ and $\infty.$

Examples

$(2,3)$ means all real numbers between $2$ and $3,$ but not including $2$ or $3.$

$[-2,0)$ means all real numbers between $-2$ and $0,$ including $-2,$ but not including $0.$

$[5, \infty)$ means all real numbers greater than or equal to $5.$

@@ Line 15: / Line 15: @@
 == Examples ==
-*  (2,3) means all real values between 2 and 3, but not including 2 and 3
+*  <math>(2,3)</math> means all real numbers between <math>2</math> and <math>3,</math> but not including <math>2</math> or <math>3.</math>
-*  [-2,0) means all real values between -2 and 0, but does not include 0
+* <math>[-2,0)</math> means all real numbers between <math>-2</math> and <math>0,</math> including <math>-2,</math> but not including <math>0.</math>
+* <math>[5, \infty)</math> means all real numbers greater than or equal to <math>5.</math>

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Difference between revisions of "Interval"

Revision as of 22:11, 16 August 2013

Definition

Symbols

Examples