1. The problem statement, all variables and given/known data 'Use differentiation to prove that as the radius of the base of a cone increases, the height of the cone decreases.' 2. Relevant equations The height has been previously calculated as: h = (507 - 2pi r^3) / pi r^2 3. The attempt at a solution I have worked out that: h' = (-1014 - 2pi r^3) / pi r^3 I'm just not sure how to do the proving section though. I can do it without differentiating by replacing values for r in the h equation and also by graphing the h equation, but that doesn't answer the question as differentiation is not used. Any help would be greatly appreciated!!