I found this proof on a website for the derivative of ln x:(adsbygoogle = window.adsbygoogle || []).push({});

y = ln x.

e^y = x,

dy/dx * e^y = 1,

dy/dx * x = 1,

dy/dx = 1/x.

My question is, why can't we use a similar method to prove the derivative of log(b)x = 1/x, like this:

y = log(b) x.

b^y = x,

dy/dx * b^y = 1,

dy/dx * x = 1,

dy/dx = 1/x.

Thanks so much everyone.

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Please correct my proof for the derivative of log x

**Physics Forums | Science Articles, Homework Help, Discussion**