How Do You Derive f(x) = 1/(ln(x)^2)?

christinee112
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Homework Statement



Find the derivative of f(x):
f(x)= 1/ ((ln(x)^2))


Homework Equations



f(x)= ln(x)
f'(x)= 1/((ln(x))

The Attempt at a Solution



Dx(1/ln(x)^2) =
Dx((ln(x))^-2)=
-2*(ln(x)^-3) * Dx(ln(x)) =
-2*(ln(x)^-3) * 1/x =
-2/(x*ln(x)^3)

Are these the correct steps? I'm getting myself confused
 
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This is correct.
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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