Question

\[= \pi \int\limits_{1}^{\infty}\frac{\sec^{3} u}{\tan^{2} u} du\]

Answer 1

improper integrals huh

Answer 2

break down sec^3 u first

Answer 3

\[\frac{\sec^{3} u}{\tan^{2} u} \]
\[\frac{\sec^{2} u}{\tan^{2} u} secudu\]