Department of Economics & Management Studies
Principles of Microeconomics: Elasticity of Demand and Market Clearing Equilibrium
COURSE: ECON-101
SEMESTER: I
Abstract: Price elasticity of demand measures the responsiveness of the quantity demanded of a good to a change in its price. Formally, it is computed as the percentage change in quantity demanded divided by the percentage change in price. When substitutes are abundantly accessible within a competitive equilibrium, elasticity increases asymptotically.
$$\varepsilon_p = \frac{\% \Delta Q_d}{\% \Delta P} = \left( \frac{\partial Q}{\partial P} \right) \cdot \left( \frac{P}{Q} \right)$$
In market environments characterized by non-linear price ceilings or external network friction, cross-price elasticity exhibits asymmetric substitution patterns. Consumer surplus diminishes proportionately when regulatory intervention restricts dynamic throughput across decentralized sub-units.
Cross-elasticity coefficients greater than unity represent elastic demand conditions, where minor adjustments in marginal costs induce substantial reallocations of aggregate purchasing behavior across localized consumer segments.