The number of solution of the equation,$\sum\limits_{r = 1}^5 {\cos (r\,x)} $ $= 0$ lying in $(0, \pi)$ is :
$2$
$3$
$5$
more than $5$
If $\sin \theta + \cos \theta = 1$ then the general value of $\theta $ is
If $\left| {\,\begin{array}{*{20}{c}}{\cos (A + B)}&{ - \sin (A + B)}&{\cos 2B}\\{\sin A}&{\cos A}&{\sin B}\\{ - \cos A}&{\sin A}&{\cos B}\end{array}\,} \right| = 0$, then $B =$
The general solution of $\tan 3x = 1$ is
If $\tan m\theta = \tan n\theta $, then the general value of $\theta $ will be in
If $\tan 2\theta \tan \theta = 1$, then the general value of $\theta $ is