6- There has been an explosion of use of antibiotic for both medical and veterinary (especially in

meat and poultry industry) purpose. The following cubic equation is an estimate of billion dozes

of antibiotic used each year over 20-year time periods (t= 1 for year 1995),

A(t) = 0.192 t 3 -2.305t 2 +10.95t+12.06

a) Calculate A(10) and A'(10). What is the interpretation of A'(10)?

b) Show that the marginal function intersect the average function at its minimum point..