Économie (discipline)L'économie (ou économie politique, science économique) est une discipline qui étudie l'économie en tant qu'activité humaine, qui consiste en la production, la distribution, l'échange et la consommation de biens et de services. Son nom provient du grec ancien / oikonomía qui signifie « administration d'un foyer ». Si dans l'Antiquité Xénophon et Aristote ont chacun écrit un traité sur l'économie, c'est à partir du que se développe la pensée économique moderne, avec le mercantilisme, puis au avec les physiocrates.
Substitute goodIn microeconomics, two goods are substitutes if the products could be used for the same purpose by the consumers. That is, a consumer perceives both goods as similar or comparable, so that having more of one good causes the consumer to desire less of the other good. Contrary to complementary goods and independent goods, substitute goods may replace each other in use due to changing economic conditions. An example of substitute goods is Coca-Cola and Pepsi; the interchangeable aspect of these goods is due to the similarity of the purpose they serve, i.
Law of demandIn microeconomics, the law of demand is a fundamental principle which states that there is an inverse relationship between price and quantity demanded. In other words, "conditional on all else being equal, as the price of a good increases (↑), quantity demanded will decrease (↓); conversely, as the price of a good decreases (↓), quantity demanded will increase (↑)". Alfred Marshall worded this as: "When we say that a person's demand for anything increases, we mean that he will buy more of it than he would before at the same price, and that he will buy as much of it as before at a higher price".
