Logarithms are the inverse functions of exponential functions. They help us solve for an exponent.
If I have , this is read “log base b of c.”
The base is the same base as the base of an exponent. The answer you get when you evaluate this is the same as the exponent. The relationship between between a and an exponent is the same as the relationship between division and multiplication.
Evaluating (easy) Logarithms
Evaluating logarithms is just about finding the number that would make the exponent work.
(3 to what power is 9?)
Common Logs & Natural Logs
Most logarithms, like the ones on your calculator, are either , written simply as , or , written as . is called common log, and is called a natural log. Most calculators have buttons for common logs and natural logs, but not any other type of log.