5.5 The Substitution Rule/21

$\int {\frac {\cos {({\sqrt {t}})}}{\sqrt {t}}}dt=\int {\sqrt {u}}$

Failed to parse (unknown function "\begin{align}"): {\displaystyle \begin{align} u &= \sqrt{u} \\[2ex] du &= \frac{1}{2} \frac{1}{\sqrt{t}\; dx \\[2ex] \frac{1}{\pi}du &= dx \end{align} }