申論題

6. A manufacturer of digital clocks determines that he can sell x clocks per week at price p where x and p are related by the equation jc2 +3xp+/?2 = 4400. This equation determines demand as a function of price, x=Q(p), near the point (p0,x0)=(40, 20). (a) If price is increasing at the rate of 50% per week how fast is demand changing when p=$40? (8points)