$\tan 75^\circ - \cot 75^\circ = $

यदि $A + B + C = \pi ,$ तो ${\tan ^2}\frac{A}{2} + {\tan ^2}\frac{B}{2} + $${\tan ^2}\frac{C}{2}$ हमेशा है

$1 + \cos 2x + \cos 4x + \cos 6x = $

$\frac{{\sin 3\theta - \cos 3\theta }}{{\sin \theta + \cos \theta }} + 1 = $

$\sin \frac{\pi }{{14}}\sin \frac{{3\pi }}{{14}}\sin \frac{{5\pi }}{{14}}\sin \frac{{7\pi }}{{14}}\sin \frac{{9\pi }}{{14}}\sin \frac{{11\pi }}{{14}}\sin \frac{{13\pi }}{{14}}$ का मान होगा

यदि $\tan A = \frac{1}{2},\tan B = \frac{1}{3},$ तब $\cos 2A = $