Find the rate of change of total revenue, cost, and profit with respect to time. Assume that R(x) and C(x) are in dollars. R(x) = 45x - 0.5x2, C(x) =2x + 15, when x =35 and dx / dt = 30 units per day The rate of change of total revenue is $ per day. The rate of change of total cost is $ per day The rate of change of total profit is $ per day