An artisan makes hand-crafted painted benches to sell at a craft mall. Her weekly revenue and costs (not including labor) are given in the table. Weekly Revenue and Costs for Hand-crafted Benches Number of benches sold each week, n 1 Weekly revenue, R (dollars) Weekly cost, C (dollars) 307 62 3 872 92 5 1365 115 7 1740 109 9 1982 149 11 1952 174 13 1709 203 (a) Find a quadratic model for revenue. (Round all numerical values to three decimal places.) R(n) = dollars Find a cubic model for cost. (Round all numerical values to three decimal places.) C(n) = dollars Using the previous models for revenue and cost, find a cubic model for profit, P. (Round all numerical values to three decimal places.) P(n)= dollars (b) Write the derivative formula for profit.