The value of $cot\, x + cot\, (60^o + x) + cot\, (120^o + x)$ is equal to :
$cot\, 3x$
$tan\, 3x$
$3\, tan \,3x$
$\frac{{3\,\, - \,\,9\,{{\tan }^2}\,x}}{{3\,\tan \,x\,\, - \,\,{{\tan }^3}\,x}}$
If $\tan A = \frac{1}{2},\tan B = \frac{1}{3},$ then $\cos 2A = $
The value of ${\cos ^2}\,{10^o}\,\, - \,\cos \,\,{10^o}\,\cos \,\,{50^o}\, + \,{\cos ^2}\,{50^o}$ is
The value of $cosec \frac{\pi }{{18}} - \sqrt 3 \,sec\, \frac{\pi }{{18}}$ is a
Let $\frac{\pi}{2} < x < \pi$ be such that $\cot x=\frac{-5}{\sqrt{11}}$. Then $\left(\sin \frac{11 x}{2}\right)(\sin 6 x-\cos 6 x)+\left(\cos \frac{11 x}{2}\right)(\sin 6 x+\cos 6 x)$ is equal to
If $\alpha ,\,\beta ,\,\gamma \in \,\left( {0,\,\frac{\pi }{2}} \right)$, then $\frac{{\sin \,(\alpha + \beta + \gamma )}}{{\sin \alpha + \sin \beta + \sin \gamma }}$ is