所屬科目:研究所、轉學考(插大)-微積分
4. A politician estimates that by campaigning in a country for x days, she will gain 2x (thousand) votes, but her campaign expenses will be 5 x 2 + 500 dollars. She wants to campaign for the number of days 2x that maximizes the number of votes per dollar, f ( x) = . For how many days should shcampaign?
7. An epidemic is spreading at the rate of new cases per day, where t is the number of days since the epidemic began. Find the total number of new cases in the first 10 days of the epidemic.
8. A subject can perform a task at the rate of tasks per minute at time t minutes. Find the total number of tasks performed from time t = 0 to time t = 12.
9. A company’s output is given by the Cobb-Douglas production function , where L and K are the numbers of units of labor and capital. Each unit of labor costs $50 and each unit of capital costs $60, and $1500 is available to pay for labor and capital. How many units of labor and of capital should be used to maximize production?