The number of solutions of the equation $x +2 \tan x =\frac{\pi}{2}$ in the interval $[0,2 \pi]$ is :

$sin 3\theta = 4 sin\, \theta \,sin \,2\theta \,sin \,4\theta$ in $0\, \le \,\theta\, \le \, \pi$ has :

Find the principal and general solutions of the equation $\sec x=2$

Let $f(x) = \cos \sqrt {x,} $ then which of the following is true

If $2{\cos ^2}x + 3\sin x - 3 = 0,\,\,0 \le x \le {180^o}$, then $x =$

If $\cos 7\theta = \cos \theta - \sin 4\theta $, then the general value of $\theta $ is