Which of the following is correct?

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

$\tan \left( \frac{\pi }{4} + \theta \right) - \tan \left( \frac{\pi }{4} - \theta \right) = $

If $\sin \theta + \cos \theta = \frac{17}{13}, 0 < \theta < 90^{\circ},$ then the value of $\sin \theta - \cos \theta$ is

If angle $\theta$ is divided into two parts such that the tangent of one part is $k$ times the tangent of the other and $\phi$ is their difference,then $\sin \theta = $

If $\operatorname{cosec} \theta - \cot \theta = p$,then the value of $\operatorname{cosec} \theta =$