ત્રિકોણ $ABC$ માં , ${\sin ^2}\frac{A}{2} + {\sin ^2}\frac{B}{2} + {\sin ^2}\frac{C}{2} = . . . .$
$1 - 2\,\cos \frac{A}{2}\cos \frac{B}{2}\cos \frac{C}{2}$
$1 - 2\,\sin \frac{A}{2}\cos \frac{B}{2}\cos \frac{C}{2}$
$1 - 2\,\sin \frac{A}{2}\sin \frac{B}{2}\sin \frac{C}{2}$
$1 - 2\,\cos \frac{A}{2}\cos \frac{B}{2}\sin \frac{C}{2}$
સાબિત કરો કે, $\frac{\cos 7 x+\cos 5 x}{\sin 7 x-\sin 5 x}=\cot x$
સાબિત કરો કે : $\frac{\sin x+\sin 3 x}{\cos x+\cos 3 x}=\tan 2 x$
$\tan \frac{A}{2} = . . .$
જો $\cos \,(\theta - \alpha ) = a,\,\,\sin \,(\theta - \beta ) = b,\,\,$ તો ${\cos ^2}(\alpha - \beta ) + 2ab\,\sin \,(\alpha - \beta ) = . . . .$
$\tan 20^\circ \tan 40^\circ \tan 60^\circ \tan 80^\circ = $