How to do question 1? had no idea how to do both parts

Differentiate both sides with respect to :



When , you have



For part (b), we now assume that and are functions of an independent variable, which we'll call (for time). Now differentiating both sides with respect to , we have



where the chain rule is used on the right side. We're told that is decreasing at a constant rate of 0.1 units/second, which translates to . So when , you have





where the unit is again units/second.