$\frac{{\cos A}}{{1 - \sin A}} = $
$\sec A - \tan A$
${\rm{cosec}}\,A + \cot A$
$\tan \left( {\frac{\pi }{4} - \frac{A}{2}} \right)$
$\tan \left( {\frac{\pi }{4} + \frac{A}{2}} \right)$
$\sqrt {\frac{{1 - \sin A}}{{1 + \sin A}}} = $
For $A = 133^\circ ,\;2\cos \frac{A}{2}$ is equal to
If $\alpha ,\,\beta ,\,\gamma \in \,\left( {0,\,\frac{\pi }{2}} \right)$, then $\frac{{\sin \,(\alpha + \beta + \gamma )}}{{\sin \alpha + \sin \beta + \sin \gamma }}$ is
$\sqrt 3 \,{\rm{cosec}}\,{20^o} - \sec \,{20^o} = $
If $\cos \left( {\alpha + \beta } \right) = \frac{4}{5}$ and $\sin \left( {\alpha - \beta } \right) = \frac{5}{{13}}$,where $0 \le \alpha ,\beta \le \frac{\pi }{4}$ . Then $\tan 2\alpha =$