$\cos A + \sin (270^\circ + A) - \sin (270^\circ - A) + \cos (180^\circ + A) = $

If $7 \sin ^{2} \theta+3 \cos ^{2} \theta=4,$ then $\tan \theta=$

In a triangle $ABC,$ the value of $\sin A + \sin B + \sin C$ is

If the roots of the quadratic equation $x^2 + px + q = 0$ are $\tan 30^\circ$ and $\tan 15^\circ$ respectively,then the value of $2 + q - p$ is

$\cos 20^\circ \cos 40^\circ \cos 80^\circ = $

If $\tan 20^{\circ} = k,$ then $\frac{\tan 250^{\circ} + \tan 340^{\circ}}{\tan 200^{\circ} - \tan 110^{\circ}} = $