The value of $$\tan \left(\frac{\pi}{8}\right)$$ is _________.

The value of $$\tan \frac{\pi}{8}$$ is

If $$\cos 2 B=\frac{\cos (A+C)}{\cos (A-C)}$$. Then $$\tan A, \tan B, \tan C$$ are in

If $$\sin 18^{\circ}=\frac{\sqrt{5}-1}{4}$$, then $$\cos ^2 48^{\circ}-\sin ^2 12^{\circ}$$ has the value

If $$\frac{\cos (A+B)}{\cos (A-B)}=\frac{\sin (C+D)}{\sin (C-D)}$$, then $$\tan A \tan B \tan C=$$

If $$\cos x=\frac{25}{24}$$ and $$x$$ lięs in first quadrant, then $$\sin \frac{x}{2}+\cos \frac{x}{2}=$$

The value of $$\sin 18^{\circ}$$ is