5.5 The Substitution Rule/67

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