9709 P13 - Jun 2017 - Q10
1329
Fig. 1 shows part of the curve \(y = x^2 - 1\) and the line \(y = h\), where \(h\) is a constant.
(i) The shaded region is rotated through 360° about the \(y\)-axis. Show that the volume of revolution, \(V\), is given by \(V = \pi \left( \frac{1}{2}h^2 + h \right)\).
(ii) Find, showing all necessary working, the area of the shaded region when \(h = 3\).
