General expression for the derivative?

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SUMMARY

The discussion focuses on finding the general form for the nth derivative of the function f(x) = 1/(x^m log x), where m is an integral value. The nth derivative is expressed as f^{(n)}(x) = (-1)^n x^{-(m+n)} ∑_{k=0}^n a_{k,n} [log(x)]^{-k}, with coefficients defined by the recurrence relation a_{k,n} = [m + (n-1)] a_{k,n-1} + (k-1) a_{k-1,n-1}. The initial conditions for the coefficients are a_{0,n} = (m + n - 1)!/(m-1)! and a_{n,n} = n!. The discussion concludes that the Leibniz rule governs the coefficients, indicating that no alternative method exists for deriving them.

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I'm trying to find the general form for the nth derivative of
[tex] f(x) = \frac{1}{x^m \log x}[/tex]

where m can be anything (set m = 1 for instance). For ease, you can take m to be integral.

It sounds surprisingly simple, but the most I've been able to say is
[tex] f^{(n)}(x) = (-1)^n x^{-(m+n)} \sum_{k=0}^n a_{k, n} [\log(x)]^{-k}[/tex]

where the coefficients satisfy
[tex] a_{k,n} = [m + (n-1)] a_{k, n-1} + (k-1) a_{k-1, n-1}[/tex]

for 0 < k < n, and with [tex]a_{0, n} = (m + n - 1)!/(m-1)![/tex] and [tex]a_{n,n} = n![/tex]

Unfortunately, I was hoping to get a general form for the coefficients. Does anyone know a trick?
 
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There is no trick. The Leibniz rule is responsible for the coefficients and you can't change that.
 

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