Intervals

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An interval is a set of numbers between upper and lower bound. To create an interval, type e.g. 2 < x < 3 in Input Bar. Interval in previous example is open. You can also define closed (2 ≤ x ≤ 3) and semi-closed (2 ≤ x < 3) intervals.

Note: See also Boolean values.

To determine whether number c belongs to interval r type r(c) into the Input Bar, the result will be a Boolean value. Generalization of intervals are Inequalities.

Commands for intervals

  • Min, Max, Midpoint for an interval with lower bound a and upper bound b return numbers a, b and \mathrm{\mathsf{ \frac{a+b}2 }} respectively. The result doesn't depend on whether the interval is open, closed or semi-closed.
  • Point returns a moveable point whose x-coordinate belongs to the interval and y-coordinate is 0.
  • PointIn returns a moveable point whose x-coordinate belongs to the interval and y-coordinate may be changed arbitrarily.
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