Re: [問題]算消費者均衡的問題

看板EconStudy作者 (reluctant)時間13年前 (2011/01/13 21:32), 編輯推噓4(401)
留言5則, 4人參與, 最新討論串2/2 (看更多)
※ 引述《suxxx (無聊新鮮人)》之銘言: : 效用涵數為U(X,Y)=X平方+Y平方,Px=10 Py=20 M=1000 求消費者均衡? : 要用Lagrange求 我真的不會 請各位幫幫忙 我今天就好人做到底吧 平常不上B,一上就PO一堆文XD U = X^0.5 + Y^0.5 預算限制式為: B = Px*X + Py*Y -M = 0 所以Lagrange式為: L(X,Y,Lampda) = U + Lampda*B 對X微分:dL/dX = 0.5X^-0.5 + Lampda*Px = 0 對Y微分:dL/dY = 0.5X^-0.5 + Lampda*Py = 0 對Lampda微分:dL/dLampda = B = 0 所以 X = (2*Lampda*Px)^-2 Y = (2*Lampda*Py)^-2 Lampda = 0.5*(M^-0.5)*(Px^-1+Py^-1)^0.5 把題目給你的東西帶進去, Lampda = (3/80000)^0.5 X = 200/3 Y = 50/3 -- Nobody ever saw a dog make a fair and deliberate exchange of one bone for another with another dog. -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 61.228.41.88

01/21 19:57, , 1F
U不是等於X平方+Y平方嗎?
01/21 19:57, 1F

01/21 23:00, , 2F
對喔....我好像搞錯了XD
01/21 23:00, 2F

01/21 23:46, , 3F
x與y的數量為2:1的關係,這樣就?
01/21 23:46, 3F

01/25 22:22, , 4F
不滿足凸性假設,還可以用L解嗎?
01/25 22:22, 4F

01/30 22:58, , 5F
此題角解X=100 U=10000
01/30 22:58, 5F
文章代碼(AID): #1DBlxYS6 (EconStudy)
文章代碼(AID): #1DBlxYS6 (EconStudy)