Chapter 6.2, Problem 9E

EXERCISES

Pollution A lake polluted by bacteria is treated with an anti-bacterial chemical. After t days, the number N of bacteria per milliliter of water is approximated by

$N(t)=20\left(\frac{t}{12}-\ln \left(\frac{t}{12}\right)\right)+30$

for $1\le t\le 15$.

a. When during this time will the number of bacteria be a minimum?

b. What is the minimum number of bacteria during this time?

c. When during this time will the number of bacteria be a maximum?

d. What is the maximum number of bacteria during this time?