Find the value of $\tan \frac{13 \pi}{12}$
We have
$\tan \frac{{13\pi }}{{12}} = \tan \left( {\pi + \frac{\pi }{{12}}} \right)$
$ = \tan \frac{\pi }{{12}} = \tan \left( {\frac{\pi }{4} - \frac{\pi }{6}} \right)$
$ = \frac{{\tan \frac{\pi }{4} - \tan \frac{\pi }{6}}}{{1 + \tan \frac{\pi }{4}\tan \frac{\pi }{6}}}$
$ = \frac{{1 - \frac{1}{{\sqrt 3 }}}}{{1 + \frac{1}{{\sqrt 3 }}}} = \frac{{\sqrt 3 - 1}}{{\sqrt 3 + 1}}$
$= 2 - \sqrt 3 $
If $A$ lies in the second quadrant and $3\tan A + 4 = 0,$ the value of $2\cot A - 5\cos A + \sin A$ is equal to
Find the value of the trigonometric function $\cot \left(-\frac{15 \pi}{4}\right)$
If $\cos A = \frac{{\sqrt 3 }}{2},$ then $\tan 3A = $
Find $\sin \frac{x}{2}, \cos \frac{x}{2}$ and $\tan \frac{x}{2}$ for $\sin x=\frac{1}{4}, x$ in quadrant $II$
The value of $\frac{{\cot 54^\circ }}{{\tan 36^\circ }} + \frac{{\tan 20^\circ }}{{\cot 70^\circ }}$ is