If $\tan (\cot x) = \cot (\tan x),$ then $\sin 2x =$
$(2n + 1)\frac{\pi }{4}$
$\frac{4}{{(2n + 1)\pi }}$
$4\pi (2n + 1)$
None of these
If $\cos {40^o} = x$ and $\cos \theta = 1 - 2{x^2}$, then the possible values of $\theta $ lying between ${0^o}$ and ${360^o}$is
The set of angles btween $0$ & $2\pi $ satisfying the equation $4\, cos^2 \, \theta - 2 \sqrt 2 \, cos \,\theta - 1 = 0$ is
$\alpha=\sin 36^{\circ}$ is a root of which of the following equation
The number of elements in the set $S=\left\{x \in R : 2 \cos \left(\frac{x^{2}+x}{6}\right)=4^{x}+4^{-x}\right\}$ is$.....$
All possible values of $\theta \in[0,2 \pi]$ for which $\sin 2 \theta+\tan 2 \theta>0$ lie in