An interval refers to a set containing all real numbers between two specific real numbers, and may also contain two real numbers.

In mathematics, an interval usually refers to a set of real numbers: if X and Y are two numbers in a set, then any number between X and Y also belongs to the set.

A common concept in middle school mathematics belongs to the field of mathematics, which refers to a continuous range. Any continuous block of the rationing object is called an interval; An interval is also called an extension, because when it runs out of allocated intervals, a new record must be inserted and a new interval must be allocated.

Once an interval is assigned to an object or table, index and cluster, it cannot be assigned to other objects. It is divided into closed interval, open interval and semi-open and semi-closed interval.

Let a, bR and a? The set of real numbers x satisfying the inequality axb is called a closed interval and expressed as [a, b];

Satisfy inequality a and inequality ax. The real numbers a and b here are called the endpoints of the corresponding interval.

On the number axis, these intervals can be represented by line segments with endpoints A and B. In the figure, the endpoints included in the interval are represented by solid lines, and the endpoints not included in the interval are represented by hollow points.

For example, buses are added between the two end points. For example, the normal line No.2 is the shuttle bus from Yanming Lake to Changchun Station, which is the wheel factory added between this line and Changchun Station. Generally, there are too many passengers on this line, and only those who can't get on the bus will work overtime.