Chapter 4.2, Problem 89E

Revenue. A dairy is planning to introduce and promote a new line of organic ice cream. After test marketing the new line in a large city, the marketing research department found that the demand in that city is given approximately by

     $\begin{array}{cccc}p& =& 10e^{-x}& 0\le x\le 5\end{array}$

where x thousand quarts were sold per week at a price of $p each.

1. (A) Find the local extrema for the revenue function.
2. (B) On which intervals is the graph of the revenue function concave upward? Concave downward?