If$\cos 6\theta + \cos 4\theta + \cos 2\theta + 1 = 0$, where $0 < \theta < {180^o}$, then $\theta  =$

Find the general solution of the equation $\sin 2 x+\cos x=0$

The solution set of the equation $tan(\pi\, tanx) = cot(\pi\, cot\, x)$ is

The value of the expression

$\frac{{\left (sin 36^o + cos 36^o - \sqrt 2  sin 27^o)( {\sin {{36}^0} + \cos {{36}^0} - \sqrt 2 \sin {{27}^0}} \right)}}{{2\sin {{54}^0}}}$ is less than

Number of solutions of $\sqrt {\tan \theta }  = 2\sin \theta ,\theta  \in \left[ {0,2\pi } \right]$ is equal to 

The general value of $\theta $ in the equation $2\sqrt 3 \cos \theta = \tan \theta $, is