Log-log Example

Suppose that f(n) = 25 * n² .

n	f(n)
2	100
3	225
4	400
5	625
6	900

The log-log graph makes it obvious that f(n) is O(n²): if the slope of the line is k, the function is O(n^k).

The points that are plotted from the function lie on a straight line that is parallel to a known O(n²) line.