Question

integral of tan 5Θ dΘ

Answer 1

I got that 5Θ is your u
and
the du is 5dΘ
but I'm not sure what to do next

Answer 2

\[\int\tan5\theta~d\theta=\int\frac{\sin5\theta}{\cos5\theta}~d\theta\]
Substitute \(u=\cos5\theta\), then \(du=-5\sin5\theta~d\theta\), so the integral becomes
\[-\frac{1}{5}\int\frac{du}{u}\]