All edges of a cube are growing at the same rate. The length, l, in cm of each edge of the cube at t minutes is given by the function l = √(2t + 1).
a) Express the volume of the cube as a function of time, t.
b) Express the surface area of the cube as a function of time, t..
c) Calculate the volume and the surface area of the cube at t = 4 minutes.