\( \definecolor{colordef}{RGB}{249,49,84} \definecolor{colorprop}{RGB}{18,102,241} \)
Let \(f\) be the function defined on \(\mathbb{R}^*\) by \(f(x) = \dfrac{e^x}{x}\).
Determine the derivative function \(f'\):
\(f'(x) = \)