【摘要】 本文介绍和证明了同一商品的总收益弹性与需求弹性守恒定理［１］及其推论，获得了一个重要公式，即ＥＲ±Ｅｄ＝１（ＥＲ即商品的总收益弹性，Ｅｄ即需求弹性）并以市场上常见的商品为例，列举了这一公式在经济预测决策方面的种种应用。更多还原

【Abstract】 In this paper, we have proved conservation the law of elasticity of revenue function and demand function about the same kind of goods and its corollary. We have abtained the other important formula: E R±E d=1 (E R .i.e revenue elasticity, E d .i.e demand elasticity). And taking customary goods on the market, for instance, the paper discusses some applications of economics forecasting of the law.更多还原