$\sqrt 3 \,{\rm{cosec}}\,{20^o} - \sec \,{20^o} = $
$2$
$\frac{{2\,\sin {{20}^o}}}{{\sin {{40}^o}}}$
$4$
$\frac{{4\,\sin {{20}^o}}}{{\sin {{40}^o}}}$
જો $90^\circ < A < 180^\circ $ અને $\sin A = \frac{4}{5},$ તો $\tan \frac{A}{2} = . . .$
જો $\sin A + \cos A = \sqrt 2 ,$ તો ${\cos ^2}A = $
$\cos \frac{\pi }{7}\cos \frac{{2\pi }}{7}\cos \frac{{4\pi }}{7} = $
${\sin ^2}\frac{\pi }{8} + {\sin ^2}\frac{{3\pi }}{8} + {\sin ^2}\frac{{5\pi }}{8} + {\sin ^2}\frac{{7\pi }}{8}$ =
જો $\alpha + \beta + \gamma = 2\pi ,$ તો