यदि $\tan A = \frac{1}{2},$ तो $\tan 3A = $

${(\cos \alpha + \cos \beta )^2} + {(\sin \alpha + \sin \beta )^2} = $

${\rm{cosec }}A - 2\cot 2A\cos A = $

यदि $\tan \theta = \frac{{\sin \alpha - \cos \alpha }}{{\sin \alpha + \cos \alpha }},$ तो $\sin \alpha + \cos \alpha $ व $\sin \alpha - \cos \alpha $ बराबर होंगे

यदि $\tan \alpha = \frac{1}{7}$ तथा  $\sin \beta = \frac{1}{{\sqrt {10} }}\left( {0 < \alpha ,\,\beta < \frac{\pi }{2}} \right)$, तब  $2\beta $ बराबर है

$\sin 10^{\circ} \sin 30^{\circ} \sin 50^{\circ} \sin 70^{\circ}$ का मान है