Logarithm

A logarithm of a number is the exponential power to which you raise the base to obtain the number.

For high school algebra, the most common base is "10". For base 10, the definition becomes as follows: A logarithm of a number is the power to which you raise 10 to obtain the number.

For example, the logarithm of 100 is the power to which you raise 10 to obtain 100. Because 10 to the power of 2 equals 100, the logarithm of 100 is 2:

log 100 = 2 because 10² = 100

There are formulas for converting logarithms having different bases. To find a logarithm with base b using another base c, use the following identity:

$\log _{b}(x)={\frac {\log _{c}(x)}{\log _{c}(b)}}$