$1 + \cos 2x + \cos 4x + \cos 6x = $

यदि $\cos \theta  = \frac{3}{5}$ तथा $\cos \phi = \frac{4}{5},$ जहाँ $\theta $ तथा $\phi $ धनात्मक न्यूनकोण हैं, तो $\cos \frac{{\theta  - \phi }}{2} = $

$\tan 3A - \tan 2A - \tan A = $

यदि $cos A = {3\over 4} , $ तब $32\sin \left( {\frac{A}{2}} \right)\sin \left( {\frac{{5A}}{2}} \right) = $

यदि $A + B + C = {180^o},$ तो $\frac{{\tan A + \tan B + \tan C}}{{\tan A\,.\,\tan B\,.\,\tan C}} = $

$2\,{\sin ^2}\beta + 4\,\,\cos \,(\alpha + \beta )\,\,\sin \,\alpha \,\sin \,\beta + \cos \,2\,(\alpha + \beta ) = $