ID: A 19. Let f(x,y) = In(x - 2y). (a) Evaluate f(3, 1). (b) Sketch the domain of f . (c) What is the range of the function f? 20. Let f(x,y) = =2 (a) Evaluate f(3, -1). (b) Sketch the domain of f. (c) What is the range of the function f? 21. A fast-food outlet finds that the demand equation for its new side dish, "Sweetdough Tidbit", is given by 6750 P= (a + 5) 2 where p is the price (in cents) per serving and q is the number of servings that can be sold per hour at this price. At the same time, the franchise is prepared to sell q = 0.5p - 5 servings per hour at a price of p cents. Find the consumers' surplus at the equilibrium price level. a. $6.02 b. $6.06 C. $6.04 d. $6.10 e. $6.00 22. Find the first partial derivatives of the function. 1 -y a. fx = T-xfy =- ( 1 - y) 2 b. fx = Tyfy =- ( 1 + * ) 2 c. fx = Ityify=- y ( 1 + * ) 2 x d. fx = 1-y ly (1-y)2 e. fx= TYfy =- ( 1 + x ) 2 6