The cartel of copper exporting countries is called COPEC. As part of an international trade agreement, the United States has agreed to buy all the copper that COPEC wants to sell to the United States at a constant price of $100 per tonne. COPEC also sells copper in Europe at a price of $150 per tonne. COPEC acts just like a monopolist; if it finds it is profit maximising to sell in the United States at $100 per tonne and simultaneously to sell in Europe for $150 a tonne, what is the price elasticity of demand of COPEC's copper in the European market?Carefully explain all the steps in the derivation of the value of the elasticity including the underlying economic theory approach behind it.