Questions in trigonometry

Select	Question
	If $\sin \theta =\frac{12}{13},(0<\theta <\frac{\pi }{2})$ and $\cos \varphi =-\frac{3}{5},\left( \pi <\varphi <\frac{3\pi }{2} \right)$. Then $\sin (\theta +\varphi )$will be
	If $\tan A-\tan B=x$ and $\cot B-\cot A=y,$then $\cot (A-B)=$
	$\sin 12{}^\circ \sin 48{}^\circ \sin 54{}^\circ =$
	$\cos \frac{\pi }{5}\cos \frac{2\pi }{5}\cos \frac{4\pi }{5}\cos \frac{8\pi }{5}=$
	$\frac{\cos 12{}^\circ -\sin 12{}^\circ }{\cos 12{}^\circ +\sin 12{}^\circ }+\frac{\sin 147{}^\circ }{\cos 147{}^\circ }=$
	$\tan 20{}^\circ \tan 40{}^\circ \tan 60{}^\circ \tan 80{}^\circ =$
	$\cos 20{}^\circ \cos 40{}^\circ \cos 80{}^\circ =$
	$\sin 36{}^\circ \sin 72{}^\circ \sin 108{}^\circ \sin 144{}^\circ =$
	If $\cos A=m\cos B,$then
	If $x=\cos 10{}^\circ \cos 20{}^\circ \cos 40{}^\circ ,$then the value of $x$ is