Derivative of ln(ln x)

  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. jcsd
  3. tiny-tim

    tiny-tim 26,054
    Science Advisor
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    Welcome to PF!

    Hi Physicsnut! Welcome to PF! :smile:
    yes :smile:
    nooo :redface:
     
  4. Fredrik

    Fredrik 10,158
    Staff Emeritus
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    Gold Member

    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.
     
  5. HallsofIvy

    HallsofIvy 40,241
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    ##e^x##
    $$x^n$$
    [itex]\int f(x)dx[/itex]
    [tex]\frac{df}{dx}[/tex]

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

    Fredrik 10,158
    Staff Emeritus
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    The simplified tags have only been available since December 20. :smile:
     
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