If $|cos\ x + sin\ x| + |cos\ x\ -\ sin\ x| = 2\ sin\ x$ ; $x \in  [0,2 \pi ]$ , then maximum integral value of $x$ is

If $\cos 2\theta + 3\cos \theta = 0$, then the general value of $\theta $ is

If $\tan (\pi \cos \theta ) = \cot (\pi \sin \theta )$, then $\sin \left( {\theta + \frac{\pi }{4}} \right)$ equals

Let $S=\{x \in R: \cos (x)+\cos (\sqrt{2} x)<2\}$, then

The number of real solutions of the equation $2 \sin 3 x+\sin 7 x-3=0$, which lie in the interval $[-2 \pi, 2 \pi]$ is

If $A, B, C, D$ are the angles of a cyclic quadrilateral taken in order, then
$cos(180^o + A) + cos(180^o -B) + cos(180^o -C) -sin(90^o -D)=$