The solution of the equation $\left| {\,\begin{array}{*{20}{c}}{\cos \theta }&{\sin \theta }&{\cos \theta }\\{ - \sin \theta }&{\cos \theta }&{\sin \theta }\\{ - \cos \theta }&{ - \sin \theta }&{\cos \theta }\end{array}\,} \right| = 0$, is
$\theta = n\pi $
$\theta = 2n\pi \pm \frac{\pi }{2}$
$\theta = n\pi \pm {( - 1)^n}\frac{\pi }{4}$
$\theta = 2n\pi \pm \frac{\pi }{4}$
The number of solutions of the equation $\cos \left(x+\frac{\pi}{3}\right) \cos \left(\frac{\pi}{3}-x\right)=\frac{1}{4} \cos ^{2} 2 x, x \in[-3 \pi$ $3 \pi]$ is
Find the principal and general solutions of the equation $\cot x=-\sqrt{3}$
If $\cos 2\theta + 3\cos \theta = 0$, then the general value of $\theta $ is
The smallest positive root of the equation $tanx\, -\, x = 0$ lies on
If $\sin \theta + \cos \theta = 1$ then the general value of $\theta $ is