જો $A + B + C = {180^o},$ તો $\cot \frac{A}{2} + \cot \frac{B}{2} + \cot \frac{C}{2} = . . .$
$2\cot \frac{A}{2}\cot \frac{B}{2}\cot \frac{C}{2}$
$4\cot \frac{A}{2}\cot \frac{B}{2}\cot \frac{C}{2}$
$\cot \frac{A}{2}\cot \frac{B}{2}\cot \frac{C}{2}$
$8\,\cot \frac{A}{2}\cot \frac{B}{2}\cot \frac{C}{2}$
જો $\cos \theta = \frac{3}{5}$ અને $\cos \phi = \frac{4}{5},$ કે જ્યાં $\theta $ અને $\phi $ ધન લઘુકોણ છે , તો $\cos \frac{{\theta - \phi }}{2} = $
જો $2{\cos ^2}\theta - 2{\sin ^2}\theta = 1$,તો $\theta =$ .....$^o$
$\left( {\frac{{\sin 2A}}{{1 + \cos 2A}}} \right)\,\left( {\frac{{\cos A}}{{1 + \cos A}}} \right)= $
$\frac{{\sin \theta + \sin 2\theta }}{{1 + \cos \theta + \cos 2\theta }} = $
$1 - 2{\sin ^2}\left( {\frac{\pi }{4} + \theta } \right) = $