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. dx R(x) =40x - 0.5x~, C(x) =4x+ 5, when x =25 and dt = 20 units per day The rate of change of total revenue is $ 300 per day. The rate of change of total cost is $ 80 per day. The rate of change of total profit is $ 220 per day