Click here to purchase the entire book in PDF format. Warning I once learned that you should never assume, because when you assume you make an ass out of you and me... (get it? ass|u|me... okay... dumb joke). One small problem with logarithms is the way they're written. People usually don't write the base of the log so you'll see things like log(3) written which usually means $\log_{10} 3$ - if the base isn't written, it's assumed to be 10. This also holds true on most calculators. Punch in 100 and hit LOG and see if you get 2 as an answer - you probably will. Unfortunately, this assumption is not true if you're using a computer to calculate your logarithms. For example, if you're using MATLAB and you type log(100) and hit the RETURN button, you'll get the answer 4.6052. This is because MATLAB assumes that you mean base $e$ (a number close to 2.7182) instead of base 10. So, if you're using MATLAB, you'll have to type in log10(100) to indicate that the logarithm is in base 10. If you're in Mathematica, you'll have to use Log[10, 100] to mean the same thing. Note that many textbooks write log and mean log$_{10}$ just like your calculator. When the books want you to use log$_{e}$ like your computer they'll write ``ln'' (pronounced ``lawn'') meaning the natural logarithm. The moral of the story is: BEWARE! Verify that you know the base of the logarithm before you get too many wrong answers and have to do it all again.