Why elasticity is important for economic analysis? 

Elasticity is a significant concept in understanding the incidence of indirect taxation, marginal concepts as they relate to the theory of the firm, distribution of wealth and dissimilar types of goods as they relate to the theory of consumer choice and the Lagrange Multiplier. Elasticity is also crucially significant in any discussion of welfare distribution: in particular consumer surplus, producer surplus, or government surplus. The method of Elasticity was also an significant component of the Singer-Prebisch Thesis which is a central argument in Dependency Theory as it relates to development economics.