# Derivative of ln(ln x)

1. ### Physicsnut

1
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. ### tiny-tim

26,043
Welcome to PF!

Hi Physicsnut! Welcome to PF!
yes
nooo

3. ### Fredrik

10,470
Staff Emeritus
Surround your LaTeX code with either ## or $$. A single  doesn't work. This is deliberate, because it would have confused people who don't use LaTeX but write stuff about money. LaTeX guide for the forum. 4. ### HallsofIvy 40,673 Staff Emeritus ##e^x##$$x^n
$\int f(x)dx$
$$\frac{df}{dx}$$

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

5. ### Fredrik

10,470
Staff Emeritus
The simplified tags have only been available since December 20.