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

The polar co-ordinates of the point whose cartesian co-ordinates are $$(-2,-2)$$, are given by

If $$x \cos \theta+y \sin \theta=5, x \sin \theta-y \cos \theta=3$$, then the value of $$x^2+y^2=$$

If $$\sin \theta=-\frac{12}{13}, \cos \phi=-\frac{4}{5}$$ and $$\theta, \phi$$ lie in the third quadrant, then $$\tan (\theta-\phi)=$$