How do you find the derivative of ln(ln x)ln(lnx)?

1 Answer
May 13, 2015

Using chain rule and, after that, logarithm's derivation rule.

In order to use the chain rule, let's consider your function ln(u)ln(u), where evidently uu stands for lnxlnx.

Derivating ln(u)ln(u), we get (u')/u, where u' is the derivative of our u, which we have already stated is lnx.

Proceeding, (dln(lnx))/(dx) = ((1/x)/lnx) = 1/(x*lnx).