Example: log(n) ë O(n1/2).
lThis holds provided 1/n ë O(n-1/2), according to the derivative rule.
lApply the limit rule:
    lim ((1/n) / n-1/2)
 = lim (1/ n1/2)
 = 0
lThis bound is not tight, since the limit is 0.
lTherefore n-1/2 ì O(1/n).