[考試] 彈性問題

[hill9978 (不黑的小黑)]

來源: 94政大企研

科目: 個體經計  彈性章節

問題: Suppose that the price elasticity of demand for a product is +1 and that

      the price elasicity of supply is +1. Assume also that income elasticity

      of demand is +2. Then and increase in income of 10% will raise

      equilibrim price by

      (a) 10%  (b) 5%  (c) 20%  (d) an annual amount that cannt be determined

      答案是a

我的想法:

      題目已經給了income elasticity = 2 = ΔQd/Qd / ΔM/M

      那當ΔM/M 為10%時，表示ΔQd/Qd = 20%

      代入price elasticity ΔQd/Qd / ΔPx/Px = 1

      所以ΔPx/Px =20%??  可以這樣解釋嗎??

      這樣解釋跟答案好像又不太對  是少考慮了哪方面??

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→ catloveme:先假設隱含數模型，再全微化成矩陣，可得
→ catloveme:dQ/Q=[εm/(εd+εs)]*(dM/M) 其中εd=-ΔQd/Qd / ΔP/P
→ catloveme:dQ/Q=[2/(1+1)]*10%=10%
→ hill9978:可以請問我這樣的說法合理嗎??  感覺隱函數這個有點難
→ hill9978:想到  還是說有更直覺的想法??