La Microeconomie du Consommateur : Utilité, Budget et Optimum de Consommation[The Consumer Microeconomics: Utility, Budget and Consumption optimum]

This manuscript provides a discussion of some key concepts of neoclassical microeconomics focusing on consumer theory. The work is organized into three chapters. In the first chapter, we conduct a broad discussion on the notion of consumer preference and its translation in terms of utility function. In this chapter, several types of utility function (defined according to the degree of substitutability of goods) are studied. These functions include the Cobb-Douglas type utility functions (weakly substitutable goods), the linear functions (perfectly substitutable goods) and Leontief type functions (complementary goods). The second chapter is devoted to the study of the consumer's budget constraint. In this chapter, several notions are presented including the concept of budget line and consumption set. We also introduce the notion of displacement of budget line and variation of consumption set as results of economic and fiscal policies changes but also as results of exogenous price changes. The third chapter is devoted to the study of consumer utility maximization behavior under her budget constraint. This behavior is presented as optimization program allowing to derive optimal demands expressed as function of prices and income.