If $540^{\circ}<\theta<630^{\circ}$ and $\tan \theta=5 / 12$, then

$$ \frac{\cos \frac{\theta}{2}-5 \sin \frac{\theta}{2}}{\sqrt{-(12 \sec \theta+5 \operatorname{cosec} \theta)}}= $$

If $A+B+C+D=2 \pi$, then $\cos A-\cos B+\cos C-\cos D=$

If $\cosh x=\frac{4}{3}$, then $3 \cosh x+3^2 \cosh 2 x+3^3 \cosh 3 x=$

$$ \text { If } \frac{2 \sin \theta}{1+\cos \theta+\sin \theta}=y, \text { then } \frac{1-\cos \theta+\sin \theta}{1+\sin \theta}= $$