Complements
Definition. Complements are goods that are in joint demand and tend to be consumed together, so that a fall in the price of one good tends to raise the quantity demanded of the other good. Familiar examples include cars and petrol, or printers and the ink cartridges they require.
They have a negative cross elasticity of demand, since a rise in the price of one good reduces demand for the other. The stronger the complementary link, the larger the magnitude of this negative value.
This term belongs to Income and Cross Elasticity of Demand in A Level Economics. Read the full chapter for the diagrams, worked examples and exam technique.
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