If $\tan x = \frac{b}{a},$ then $\sqrt {\frac{{a + b}}{{a - b}}} + \sqrt {\frac{{a - b}}{{a + b}}} = $
$\frac{{2\sin x}}{{\sqrt {\sin 2x} }}$
$\frac{{2\cos x}}{{\sqrt {\cos 2x} }}$
$\frac{{2\cos x}}{{\sqrt {\sin 2x} }}$
$\frac{{2\sin x}}{{\sqrt {\cos 2x} }}$
If $\sin \theta = \frac{1}{2}\left( {\sqrt {\frac{x}{y}\,} + \,\sqrt {\frac{y}{x}} } \right)\,,\,\left( {x,y \in R\, - \{ 0\} } \right)$. Then
If $\sin 2\theta + \sin 2\phi = 1/2$ and $\cos 2\theta + \cos 2\phi = 3/2$, then ${\cos ^2}(\theta - \phi ) = $
$\sin {20^o}\,\sin {40^o}\,\sin {60^o}\,\sin {80^o} = $
If $90^\circ < A < 180^\circ $ and $\sin A = \frac{4}{5},$ then $\tan \frac{A}{2}$ is equal to
The expression $\frac{{\cos 6x + 6\cos 4x + 15\cos 2x + 10}}{{\cos 5x + 5\cos 3x + 10\cos x}}$ is equal to