The interval notation is used to report domains and ranges. It uses brackets and parentheses. Brackets are used if the solution includes the point on the curve. In other words, this is used when the inequality has the ≤ or ≥ symbol. Parentheses are used if the inequality symbols are just < or >. It means that the solution does not include the points on the curve, but on the data points that are greater or lower. For example, if the domain is 2<x≤8, the inerval is written as: (2,8].
