Question

What is the derivative of `f(x)=ln(ln(x))`?

Answer 1

`1/(xln(x))`

Explanation:

According to the chain rule, `d/dx[ln(u)]=u'*1/u`, and we have `u=ln(x)`, hence

`f'(x)=d/dx[ln(x)]*1/(ln(x))=1/x*1/(ln(x))=1/(xln(x))`