IntervalMemberQ

IntervalMemberQ[interval, x] gives True if x lies within the interval, and False otherwise.

IntervalMemberQ[interval1, interval2] gives True if interval2 is completely contained in interval1.

Examples

Check membership:

IntervalMemberQ[Interval[{0, 10}], 5]
(* True *)

IntervalMemberQ[Interval[{0, 10}], 15]
(* False *)

Please visit the official Wolfram Language Reference for more details.