how to do logarithms

The logarithm is the power to which the base is raised to get a certain number. What's that? You want it in English? Well, OK...

Let's start with base 10 logarithms. (For this paragraph, "log" will mean base 10 log.) If I say the log of 1,000 is 3, this means that 10 (the base) raised to the third power (log = 3) equals 1,000. (Also note that the third root of 1,000 is 10.) So log 100 = 2, log 1,000,000 = 6, etc. Logs need not be integers; the log of 25,000 is approximately 4.39794 because 10 raised to the 4.39794 power is about 25,000. Note that 4.39794 falls between 4 (log 10,000 = 4) and 5 (log 100,000 = 5).

Logs do not have to be base 10. You will probably encounter natural logs (ln), in which the base is e (2.71828...). For example e squared is approximately 7.389. So ln 7.389 = 2.

## Comments

Morgan,

That's a fairly broad topic :) Do you have a couple of example problems you'd like us to look at?

Thanks,

-Skyler