$\sin 15^{\circ}$ નું મૂલ્ય શોધો.
We have
$\sin {15^\circ } = \sin \left( {{{45}^\circ } - {{30}^\circ }} \right)$
$ = \sin {45^\circ }\cos {30^\circ } - \cos {45^\circ }\sin {30^\circ }$
$ = \frac{1}{{\sqrt 2 }} \times \frac{{\sqrt 3 }}{2} - \frac{1}{{\sqrt 2 }} \times \frac{1}{2} = \frac{{\sqrt 3 - 1}}{{2\sqrt 2 }}$
જો $\sin \theta + {\rm{cosec}}\theta = {\rm{2}}$, તો ${\sin ^2}\theta + {\rm{cose}}{{\rm{c}}^{\rm{2}}}\theta = $
$1 - \frac{{{{\sin }^2}y}}{{1 + \cos \,y}} + \frac{{1 + \cos \,y}}{{\sin \,y}} - \frac{{\sin \,\,y}}{{1 - \cos \,y}} =$
$\cos 1^\circ + \cos 2^\circ + \cos 3^\circ + ..... + \cos 180^\circ = $
મૂલ્ય શોધો. $\cot \left(-\frac{15 \pi}{4}\right)$
જો $(\sec \alpha + \tan \alpha )(\sec \beta + \tan \beta )(\sec \gamma + \tan \gamma )$
$ = \tan \alpha \tan \beta \tan \gamma $, તો $(\sec \alpha - \tan \alpha )(\sec \beta - \tan \beta )$$(\sec \gamma - \tan \gamma ) = $