What is Interval?

A set of points lying between any two points “a” and “b” is known as an Interval.

For example:

the interval from points x=1 to x=10 is the set of points lying between 1 and 10.

Open and Closed Interval:

An Interval which includes it’s end points(a and b)  is known as Closed interval ; While an Interval Which does not includes it’s end points(a and b)  is known as Open Interval.

A open Interval from point “a” to point “b” is denoted by:

(a,b)

and  A closed Interval from point “a” to point “b” is denoted by:

[a,b]

For example:

The open and closed interval from point “a” to “b” where a=1 and b=5 are:

(a,b)={2,3,4}

[a,b]={1,2,3,4,5}