【正文】
?發(fā)散型蛛網(wǎng)的條件: 供給彈性 需求彈性,或,供給曲線斜率 需求曲線斜率(絕對值)。 Ey0, inferior good 0 Ey1, Necessity; Ey1, Luxury 24 需求交叉彈性 Crossprice elasticity of demand ? Definition: It measures how the quantity demanded of one good changes as the price of another good changes. ? It is calculated as : Percentage change in quantity of good x Exy= Percentage change in the price of good y 25 ? Formula: ΔQy/Qy ΔQy Px Exy = —— or = — — ΔPx/Px ΔPx Qy ? Classification: Exy0, Substitute 替代品; Exy0, plement 互補品 。每天前往電信部門登記裝電話的客戶絡(luò)繹不絕,最高一天甚至超過以前一天登記數(shù)的10倍。1 Chapter 3 Elasticity Theory 2 The contents of the chapter ? is elasticity? ? 2. Elasticity of Demand ? 3. Elasticity of Supply 3 is elasticity? ? 彈性 elasticity: 自變量變動一個百分比所引起的因變量變動的百分比 。蕭山區(qū)甚至出現(xiàn)了一個月發(fā)展農(nóng)村電話 萬戶的高峰,一個月新裝電話農(nóng)戶就超過以往一年的數(shù)量。 Exy=0, irrelation 不相關(guān) 26 Elasticity of Supply ?定義 Definition ?公式與計算 Formula and putation ?分類及影響因素 Classification and affect factors 27 定義 Definition ?It measures how much the quantity supplied responds to changes in the price. ? It is calculated as: Percentage change in quantity supplied Es= Percentage change in price 28 Computation: The formula for arc price elasticity of supply ΔQ Pa Es= —— ? —— (Es from a to b) ΔP Qa ΔQ Pb Es= —— ? —— (Es from b to a) ΔP Qb 29 ?Middle point Es formula ΔQ/( Qa+Qb) /2 ΔQ Pa+Pb Es = ———————— or = — ——— ΔP/( Pa+Pb) /2 ΔP