Logarithm
From ACT Wiki
1.
The mathematical function which is the inverse of "raising to the power of".
Usually abbreviated to "log".
Example
Working with logarithms to the base 10:
log10(100) = 2
And 102 = 100
More generally with logarithms to the base n:
logn(x) = the power which, when 'n' is raised to it = x
Example
10(log10(x)) = x
And, more generally, n(logn(x)) = x
2.
The logarithm to the base 10.