Let the body's reaction to a drug be measured by R(d) = d² (c/2-d/3).
c is the maximum amount of drug given, d is the dosage and R(d) is the body's reaction.
Let S(d) be the sensitivity to the drug, measured by the derivative, R' (d).
Find S(d): Find the dosage for which there is maximum sensitivity to the drug. Use c = 5.
Maximum sensitivity occurs when d=