The value of the expression $1 - \frac{{{{\sin }^2}y}}{{1 + \cos \,y}} + \frac{{1 + \cos \,y}}{{\sin \,y}} - \frac{{\sin \,\,y}}{{1 - \cos \,y}}$ is equal to
$0$
$1$
$\sin \,y$
$\cos \,y$
Prove that: $\frac{(\sin 7 x+\sin 5 x)+(\sin 9 x+\sin 3 x)}{(\cos 7 x+\cos 5 x)+(\cos 9 x+\cos 3 x)}=\tan 6 x$
$\cos 1^\circ + \cos 2^\circ + \cos 3^\circ + ..... + \cos 180^\circ = $
The value of $\tan ( - 945^\circ )$ is
Find the value of $\cos \left(-1710^{\circ}\right)$.
The value of $\cot \frac{\pi}{24}$ is :