5.5 The Substitution Rule/67

$\int _{e}^{e^{4}}{\frac {dx}{x{\sqrt {lnx}}}}$ = $\int _{1}^{4}{\frac {1}{u}}du$ = $\int _{1}^{4}u^{-1/2}du$ = Failed to parse (syntax error): {\displaystyle \frac{u^{1/2}{1/2}\bigg|_{1}^{4}}