A market research department is recommending a new headphone set for MP3 players to the production and marketing department. Once marketing testing complete the market research department presents the following demand equation: = 10 0.001 where x is the number of headphones that retailers are likely to buy at $p per set.

The financial department provides the cost function: () = 7000 + 2

(a) Find the marginal profit for 2000 headphones.

(b) Compute the approximate changes in profit if the number of headphones is increase from 2000 to 3100. Interpret your answer.