The function is  and the interval is .

The function is a greatest integer function of a real number .

For all real numbers , the greatest integer function returns the largest integer less than or equal to .

In other words, the greatest integer function rounds down a real number to the nearest integer.

To find the absolute extreme of function in given region , sketch the function .

Left end point is minimum point over the interval .

Right end point is maximum point over the interval ​.

Minimum point is .

Maximum point is .