(a)[4]
Find the exact coordinates of A.
(b)[4]
Find the volume of revolution after the shaded region is turned through $360^\circ$ about the $x$-axis. Give your answer in the form $\frac{\pi}{a}(b\sqrt{c}-d)$, where $a$, $b$, $c$ and $d$ are integers.
(c)[2]
Find a precise expression for the perimeter of the shaded region.