Please explain the graph of int(x)

[Curd]

i do not understand why they graph it with a line and a circle. I know what the circle and the line mean, i just do not understand how they apply to this graph.

 

[Mark44]

i do not understand why they graph it with a line and a circle. I know what the circle and the line mean, i just do not understand how they apply to this graph.

Are you talking about the greatest integer function that looks like this?
$$\lfloor x\rfloor$$

If so, the greatest integer function is defined as the largest integer that is less than or equal to x.
$$\lfloor 2.0\rfloor = 2$$
$$\lfloor 2.5\rfloor = 2$$
$$\lfloor 2.99\rfloor = 2$$
$$\lfloor 3.0\rfloor = 3$$

The function has a jump of one unit at each integer value.