We have seen how logarithms can be used to simplify calculations, by converting a problem involving multiplication into one needing only addition. We have also seen how statements involving exponentials can be converted into statements involving logarithms.
Logarithmic functions are the inverse of exponential functions.
The inverse of this function must be a logarithm with base e . This is written as lnx and is called the natural or naperian logarithm. John Napier, the Scottish mathematician who is often credited with inventing logarithms used a logarithm to a base quite close to e . Hence his name is now associated with the natural logarithm. Check on your calculator that you can find the ln button.