Show that for any two bases a and b for logarithms, if a and b are both
greater than 1, then there is a constant c such that loga N ≤ c(logb N).
Thus, there is no need to specify a base in O(log N). That is, O(loga N)
and O(logb N) mean the same thing.
This is mathematics, not C++. So, = will mean equals not assignment.
First note that loga N = (loga b)(logb N).
To see this first identity just note that if you raise a to the power loga N
you get N and if you raise a to the power (loga b)(logb N) you also get N.
If you set c = (log a b) you get log a N = c(log b N).