$-\frac{\pi}{2}<\theta<\frac{\pi}{2}$

$-\frac{\pi}{3}<\theta<\frac{2 \pi}{3}$

$-\frac{2 \pi}{3}<\theta<\frac{\pi}{3}$

$-\frac{\pi}{6}<\theta<\frac{5 \pi}{6}$

$x=(2 n+1) \pi+\tan ^{-1}\left(\frac{3}{4}\right), n \in Z$

$x=2 n \pi+\tan ^{-1}\left(\frac{3}{4}\right), n \in Z$

$x=n \pi+\tan ^{-1}\left(\frac{3}{4}\right), n \in Z$

$x=n \pi \pm \tan ^{-1}\left(\frac{3}{4}\right), n \in Z$

5

8

10

12

$\sqrt{3}$

$-\sqrt{3}$

$\sqrt{5}$

$-\sqrt{5}$