Finding di one tuff any one got any ideas
A pencil holder is in the shape of an open circular cylinder of radius r cm and height h cm. The surface area of the cylinder (including the base) is 250 cm2.
Show that the volume, V , of the cylinder is given by V = 125r  .
(b) Use calculus to find the value of r for which V has a stationary value.
(c)Prove that the value of r you found in part (b) gives a maximum value for V.
(d) Calculate, to the nearest cm3, the maximum volume of the pencil holder.