A logarithm is a number that indicates an which is used to raise the logarithm's in order to get back the indicated number.
The logarithm of a positive number can be written where indicates which base has been used. The expression is read as "log, base-, of " or "base- log ".
For example, since is the exponent used to raise the base to get the number Logarithms are for negative values of
The result of a logarithm depends on the base of the logarithm. Log base 4 indicates that the base is while Log base 9 has the base If the base of the logarithm is changed the result of the logarithm becomes something else entirely.
The most common logarithms are , which are often written as for . apply to all bases.