Question 5 - A-Level Maths

Exam Board	CAIE
Module	P1 (Pure Mathematics 1)
Year	2005
Session	November
Topic	Differentiation Applications
Type	Find stationary points

Express $h$ in terms of $r$ and hence show that the volume, $V \mathrm {~cm} ^ { 3 }$, of the cylinder is given by $$V = 12 \pi r ^ { 2 } - 2 \pi r ^ { 3 }$$
Given that $r$ varies, find the stationary value of $V$.