\(f'\left(x\right)=\dfrac{1}{x}\)
\(f''\left(x\right)=-\dfrac{1}{x^2}=\dfrac{\left(-1\right)^{2-1}.\left(2-1\right)!}{x^2}\)
\(f'''\left(x\right)=\dfrac{2}{x^3}=\dfrac{\left(-1\right)^{3-1}.\left(3-1\right)!}{x^3}\)
\(\Rightarrow f^{\left(n\right)}\left(x\right)=\dfrac{\left(-1\right)^{n-1}.\left(n-1\right)!}{x^n}\)