The Maxwell Ohm Company is designing a portable Bluetooth speaker. The speaker is in the shape of a cylinder with a hemisphere at each end of the cylinder. The dimensions of the speaker, in centimetres, are illustrated in the following diagram where ! is the radius of the hemisphere, and ! is the length of the cylinder, with ! > 0 and ! ≥ 0. Write down an expression for V, the volume (cm3) of the speaker, in terms of r, l and pi