# What is the integral 1/x log(x) or lnx?

## Homework Statement

I know it is supposed to be lnx however I find something peculiar. When I integrate it in wolfram alpha they give the integral as log(x). What the heck is going on here!?!

## Answers and Replies

If you check closer on Wolfram, by log(x) they mean the natural logarithm.

ok thanks, When looking at more complex solutions sometimes there are many logx's how am I supposed to know which one is logx and which one is not really logx?

They will usually define what they use. As a rule of thumb, I find that they always tend to use the natural log, but it could happen that they don't. Just pay attention to the bottom of the equation box thingy. the derivative of ln(x) is "one over the thing inside, times the derivative of the thing inside" -- my calc professor

so, y = ln (x); y' = 1/x * 1 = 1/x

i'm not sure if this helps or not... you are asking for y given y' = 1/x ?

ok thanks guyz I precciate ya!

dextercioby
Science Advisor
Homework Helper
It's simple. The 'Mathematica' software developed by Wolfram himself or his company has the natural logarithm (aka neperian logarithm) denoted as LOG, instead of the widely used LN which is derived from <natural logarithm> spelled in Latin. Most people use LOG for the logarithm in other base than Euler's number 'e'.