Victoria Jones want to construct a time capsule. The capsule will be right circular cylinder Victoria Jones want to construct a time capsule. The capsule will be right circular cylinder of height 'h' cm, and radius 'r' cm on each end . Let the total volume of capsule be V cm^3. 1. Express V in terms of r and h. 2. The material for Cylindrical part cost 2 cents per cm^2 of surface. The material for the hemispherical caps costs 3 cents per cm^2 of surface. Find an expression for 'C' cents the total cost of the materials for the capsule in terms of 'r'. So, I did the first part which was easy and the answer was $$V=πr^2h+\frac{4}{3}πr^3$$ but i don't know how to do the second part. Can anyone help me in this. Thanks.

The area of the cylindrical part is

$$A=2\pi rh$$

and the area of the spherical part is

$$A=4\pi r^2$$ so the cost is given by:

$$C=2\times2\pi rh+3\times4\pi r^2$$