Derivative of ln(ln x)

1. Mar 5, 2012

Physicsnut

1. The problem statement, all variables and given/known data

Differentiate $$ln(lnx)$$

2. Relevant equations

3. The attempt at a solution
My solution:
Let $f(x)=lnx$, since${d/dx}ln f(x)={f'(x)/f(x)}$,
${d/dx}ln(lnx)={{1/x}/lnx}/times {1/x} ={1/x^2lnx}$.

2. Mar 5, 2012

tiny-tim

Welcome to PF!

Hi Physicsnut! Welcome to PF!
yes
nooo

3. Mar 5, 2012

Fredrik

Staff Emeritus
Surround your LaTeX code with either $or . A single  doesn't work. This is deliberate, because it would have confused people who don't use LaTeX but write stuff about money. LaTeX guide for the forum. 4. Mar 5, 2012 HallsofIvy Staff Emeritus$e^x##
$$x^n$$
$\int f(x)dx$
$$\frac{df}{dx}$$

Wow! All this time I have been using "itex" and "tex"!

5. Mar 5, 2012

Fredrik

Staff Emeritus
The simplified tags have only been available since December 20.