intervals

In Mathematics, a (real) interval is a set of Real Numbers with the property that any number that lies between two numbers in the set is also included in the set. There are different types:

- Open interval:

- Closed interval:

- Half open interval:

- Intervals with infinite endpoint:

- An open interval centered at (about) a is the open interval:

  Exercise 1: Draw these intervals:

  a) (-∞,5)     b) E(-1,2)     c) [-3,∞)     d) E(1,2)     e) (-5,-1]