A short clip based on question Ch 6 #21 that discusses the special case where consumers only want to buy at most one unit of a commodity. The example shows that Market demand can be more or less elastic not by willingness of buyers to buy more or less, but because additional buyers will enter or exit from the “margin” of trade. First we simply construct the aggregate demand curve from the [horizontal sum of] individual demand curves – both of which have a staircase shape – then we interpret what is meant by the marginal consumer, intra marginal consumers, extra marginal consumers …..in a market, at a given price. The concepts of intensive and extensive margins of a market are explained.
This clip may (but maybe not!) a little clearer than how it was explained in call (May 25)