Logarithm

Part of mathematics. They are related to exponential functions. A logarithm tells what exponent (or power) is needed to make a certain number, so logarithms are the inverse of exponentiation. Historically, they were useful in multiplying or dividing large numbers. - Simple English Wikipedia

Logarithms are the inverse operation of exponentiation. We can use logarithms to find the exponent, to which a given base number must be raised in order to produce a particular result.
- Khan Academy

Logarithm it’s inverse of exponents.

means, I need to get a number X, where , and result is ====. Here is exponent and is inverse of exponent.

One method of finding logarithm is dividing number until we get a 1 as result, for example, how to find with this method?
How many times need to divide 2 to get 1 as result . So answer is 11.

In computer science, unlike in math when we’re saying , we actually shorthand for saying ====.

References