Intervals (Closed and open)

Closed interval

The set of all real numbers x such that a≤x≤b ( a and b are also real numbers) is called a closed interval and is denoted by [a,b].

Open interval

The set of all real numbers x such that a is l.t.x is l.t. b ( a and b are also real numbers) is called a one interval and is denoted by (a,b).