For q units of a product, a manufacturer's cost is C(q) dollars and revenue is R(q) dollars, with C(500)=7600,R(500)=9800. MC(500)=18, and MR(500)=24. (a) What is the profit or loss at'i =500 ? The is S (b) If production is increased from 500 to 501 units, by approximately how much does profit change? The change in profit is $