જો $\cos 3\theta = \alpha \cos \theta + \beta {\cos ^3}\theta ,$ તો $(\alpha ,\beta ) = $

$\frac{{\sin \theta + \sin 2\theta }}{{1 + \cos \theta + \cos 2\theta }} = $

જો $a\tan \theta = b$, તો $a\cos 2\theta + b\sin 2\theta = $

$\frac{{\sin 3A - \cos \left( {\frac{\pi }{2} - A} \right)}}{{\cos A + \cos (\pi + 3A)}} = $

જો $\alpha $ સમીકરણ $25{\cos ^2}\theta + 5\cos \theta - 12 = 0$, $\pi /2 < \alpha < \pi $, નું એક બીજ હોય તો $\sin 2\alpha   = . . .$

$\frac{{\sin {{81}^o} + \cos {{81}^o}}}{{\sin {{81}^o} - \cos {{81}^o}}}$=