(Maple) A monopolistic producer charges different prices at home and abroad.
The demand functions of the domestic and foreign markets are given by
$$
P_{1}+Q_{1}=100 \quad \text { and } \quad P_{2}+2 Q_{2}=80
$$
respectively. The firm's total cost function is
$$
\mathrm{TC}=\left(Q_{1}+Q_{2}\right)^{2}
$$
(a) Show that the firm's profit function is given by
$$
\pi=100 Q_{1}+80 Q_{2}-2 Q_{1}^{2}-3 Q_{2}^{2}-2 Q_{1} Q_{2}
$$
Use calculus to show that profit is maximized when \(Q_{1}=22\) and \(Q_{2}=6\),
and find the corresponding prices.
(b) The foreign country believes that the firm is guilty of dumping because
the good sells at a higher price in the home market, so decides to restrict
the sales to a maximum of 2 , so that \(Q_{2} \leq 2\). By plotting \(\pi\) in the
region \(0 \leq Q_{1} \leq 30,0 \leq Q_{2} \leq 2\), explain why the profit is
maximized when \(Q_{2}=2\). Use calculus to find value of \(Q_{1}\), and compare
the corresponding profit with that of the free market in part (a).