Intervals

Intervals contain all real numbers in a defined range. There are 3 types of intervals:

• Open interval (a,b): Does not include extremes

$(a,b) = \{x/ a < x < b\}$

• Closed interval [a,b]: Yes, it includes extremes

$[a,b] = \{x/ a \leq x \leq b\}$

• Semi-closed/semi-open interval [a,b) , (a,b] : Includes only one end

$[a,b) = \{x/ a \leq x < b\}$

$(a,b] = \{x/ a < x \leq b\}$

Graphical representation