$\tan \frac{A}{2}$ is equal to
$ \pm \sqrt {\frac{{1 - \sin A}}{{1 + \sin A}}} $
$ \pm \sqrt {\frac{{1 + \sin A}}{{1 - \sin A}}} $
$ \pm \sqrt {\frac{{1 - \cos A}}{{1 + \cos A}}} $
$ \pm \sqrt {\frac{{1 + \cos A}}{{1 - \cos A}}} $
If $cos A = {3\over 4} , $ then $32\sin \left( {\frac{A}{2}} \right)\sin \left( {\frac{{5A}}{2}} \right) = $
$\frac{{\cos A}}{{1 - \sin A}} = $
$\frac{{\sin \theta + \sin 2\theta }}{{1 + \cos \theta + \cos 2\theta }} = $
If ${\tan ^2}\theta = 2{\tan ^2}\phi + 1,$ then $\cos 2\theta + {\sin ^2}\phi $ equals
The value of $\sin 600^\circ \cos 330^\circ + \cos 120^\circ \sin 150^\circ $ is