$\cos 20^\circ \cos 40^\circ \cos 80^\circ = $
$1/2$
$1/4$
$1/6$
$1/8$
$\sqrt 2 + \sqrt 3 + \sqrt 4 + \sqrt 6 = . . ..$
જો $\cos \left( {\alpha + \beta } \right) = \frac{4}{5}$ અને $\sin \left( {\alpha - \beta } \right) = \frac{5}{{13}}$,કે જ્યાં $0 \le \alpha ,\beta \le \frac{\pi }{4}$. તો $\tan 2\alpha $ મેળવો.
જો $\frac{{5\pi }}{2} < x < 3\pi $,હોય તો $\frac{{\sqrt {1 - \sin x} + \sqrt {1 + \sin x} }}{{\sqrt {1 - \sin x} - \sqrt {1 + \sin x} }}$ =
જો $\alpha + \beta + \gamma = 2\pi ,$ તો
$\frac{{\tan {{70}^o} - \tan {{20}^o}}}{{\tan {{50}^o}}} = $