Closed interval

A closed interval is a range of numbers that includes both its starting and ending points. For example, the interval \([a, b]\) contains every number from \(a\) to \(b\), including exactly those two points. It contrasts with an open interval, which does not include its endpoints. Closed intervals are used in mathematics to specify a set where the boundary values are part of the set, ensuring that the whole span from the start to the end, including the limits, is considered.