Questions in trigonometry

Select	Question
	If $\cos \theta =\frac{1}{2}\left( a+\frac{1}{a} \right),$then the value of $\cos 3\theta $is
	If $\alpha $ is a root of $25{{\cos }^{2}}\theta +5\cos \theta -12=0$, $\pi /2<\alpha <\pi $, then $\sin 2\alpha $is equal to
	For $A=133{}^\circ ,\ 2\cos \frac{A}{2}$is equal to
	If $90{}^\circ
	If $2\tan A=3\tan B,$then $\frac{\sin 2B}{5-\cos 2B}$is equal to
	.Given that $\cos \left( \frac{\alpha -\beta }{2} \right)=2\cos \left( \frac{\alpha +B}{2} \right)$, then $\tan \frac{\alpha }{2}\tan \frac{\beta }{2}$is equal to
	If $\tan \frac{\theta }{2}=t,$then $\frac{1-{{t}^{2}}}{1+{{t}^{2}}}$is equal to
	If $\sqrt{x}+\frac{1}{\sqrt{x}}=2\cos \theta ,$then ${{x}^{6}}+{{x}^{-6}}=$
	If $\sin 2\theta +\sin 2\varphi =1/2$ and $\cos 2\theta +\cos 2\varphi =3/2$, then ${{\cos }^{2}}(\theta -\varphi )=$
	.$\cos 2(\theta +\varphi )-4\cos (\theta +\varphi )\sin \theta \sin \varphi +2{{\sin }^{2}}\varphi =$