$$\begin{aligned} & \cos \left(36^{\circ}-A\right) \cos \left(36^{\circ}+A\right)+\cos \left(54^{\circ}+A\right) \cos \\ & \left(54^{\circ}-A\right)= \end{aligned}$$

If $$x+y=\frac{\pi}{2}$$, then the maximum value of $$\sin x \cdot \sin y$$ is

If $$a=\sin 175^{\circ}+\cos 175^{\circ}$$, then

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