International Economics 10th Edition by Paul Krugman,Maurice Obstfeld ,Marc Melitz

Exercise 3

In some economies relative supply may be unresponsive to changes in prices. For example, if factors of production were completely immobile between sectors, the production possibility frontier would be right-angled, and output of the two goods would not depend on their relative prices. Is it still true in this case that a rise in the terms of trade increases welfare? Analyze graphically.