Answer
$\theta =\dfrac {\pi }{2}+2\pi k;\theta =\dfrac {3\pi }{2}+2\pi k$
$ \theta \approx 3.99+2\pi k;\theta \approx 5.43+2\pi k$$
Work Step by Step
$4\cos \theta \sin \theta +36 > \theta =\cos \theta \left( 4\sin \theta +3\right) =0$
$\cos \theta =0\Rightarrow \theta =\cos ^{-1}\left( 0\right) \Rightarrow \theta =\dfrac {\pi }{2}+2\pi k;\theta =\dfrac {3\pi }{2}+2\pi k$
$4\sin \theta +3=0\Rightarrow \sin \theta =\dfrac {-3}{4}\Rightarrow \theta =\sin ^{-1}\left( -\dfrac {3}{4}\right) \Rightarrow \theta \approx 3.99+2\pi k;\theta \approx 5.43+2\pi k$
