【正文】 10121416182022242628300 2 4 6 8 10 12 14 16 18 20 22a 30 24 20 14 10 8 6 6 7 8 10 13 15 20 a b c d e f g 蘋果 桔子 點 桔子 蘋果 無差異曲線 ? （ 1）斜率為負值； ? （ 2）凸向原點； ? （ 3）數(shù)量無限； ? （ 4）離原點越遠，效用越高； ? （ 5）互不相交； 特點 01020300 10 20Units of good Y Units of good X I1 I2 I3 I4 I5 An indifference map Y X O U k j i I39。因此，別克在廣告中應該宣稱：“我們每一美元的質量排名第一（第二）。” 也有人指出，別克的排名應該更靠前。威爾在文章的結尾時說：“如果這則廣告說‘第五名對美國并非值得慶幸，我們?yōu)榇说狼?。?1990年 8月 23日發(fā)表的一篇題為“第五意味著告別而非高質量”的文章中指出， ‘ 我們是美國第一’就象夸大一場業(yè)余比賽的勝利，誤導球迷的情緒。根據(jù)這份報告，在新車購買后的最初 90天內，別克的質量測試排名第五，位于 Lexus、 MercedesBenz、 Toyota和Infiniti之后，但在 Honda、 Nissan、Acura、 BMW和 Mazda之前。 utility is maximised The UtilityMaximizing Rule ? the utilitymaximizing rule – this rule states a consumer should reach the same marginal utility per dollar for all products consumed – in mathematical terms: MU1 P1 MU2 P2 = ?In equilibrium higherpriced goods must yield more marginal utility than lowerpriced goods to pensate for the higher price Total and Marginal Utility from Food and Clothing Units of Food Total Utility of Food Marginal Utility of Food Marginal Utility per Dollar (P = $4) Clothing Total Utility of Clothing Marginal Utility of Clothing Marginal Utility per Dollar (P = $2) 0 0 0 0 1 25 25 6 1/4 1 20 20 10 2 41 16 4 2 34 14 7 3 53 12 3 3 44 10 5 4 62 9 2 1/4 4 50 6 3 5 68 6 1 1/2 5 54 4 2 6 72 4 1 6 57 3 1 1/2 FOOD Clothing Law of Demand and Marginal Utility ? Hypothetically changing the price and observing the utilitymaximising levels of consumption, points along the demand curve can be generated. ?Diminishing marginal utility ensures that the demand curve is downward sloping Food Utility of Food Marginal Utility of Food Marginal Utility per Dollar (P = $3) Clothing Utility of Clothing Marginal Utility of Clothing Marginal Utility per Dollar (P = $2) 0 0 0 0 1 25 25 8 1/4 1 20 20 10 2 41 16 5 1/4 2 34 14 7 3 53 12 4 3 44 10 5 4 62 9 3 4 50 6 3 5 68 6 2 5 54 4 2 6 72 4 1 1/3 6 57 3 1 1/2 Total and Marginal Utility from Food and Clothing after the Price of Food Decreases from $4 to $3 per unit FOOD Clothing $8 6 4 2 0 D a b 1 2 3 4 Units of food per period Price per unit Demand for Food Generated from Marginal Utility Consumer Surplus ? The difference between the maximum amount that a consumer is willing to pay for a given quantity of a good and what the consumer actually pays Consumer surplus is the area under the demand curve above the equilibrium market price Consumer Surplus: Mathematically ? Maximum Price = $11 ? Market Price = $6 ? Quantity Purchased = 6 ? Assume: Price drops $1 for every additional unit sold. ? Consumer Surplus = $15 $51 $36 = $15 ($11+$10+$9+$8+$7+$6) ($6 x 6) = $15 D $11 6 $10 $9 $8 $7 $6 5 4 3 2 1 D $11 6 $10 $9 $8 $7 $6 5 4 3 2 1 Total Consumer Benefits D $11 6 $10 $9 $8 $7 $6 5 4 3 2 1 Consumer’s Expense D $11 6 $10 $9 $8 $7 $6 5 4 3 2 1 Consumer Benefit Consumer Expense CONSUMER SURPLUS! $51 $36 = $15 Market Demand and Consumer Surplus ? The market demand curve is the horizontal sum of the individual demand curve for all consumers in the market ?Consumer surplus for the market demand curve is the difference between the value of total utility and the total amount paid for that consumption $2 0 Quantity per period D 1 Market Demand and Consumer Surplus 10 60 D Q P 20 40 40 $400 initial surplus $400 increase in surplus due to price reduction on initial quantity $400 = (2010)40 $100 increase in surplus from purchase of additional units of Q ? Consumer surplus can be used to measure economic welfare and to pare the effects of such concepts as –Different market structures –Different tax structures –Different public expenditure programs 物以稀為貴 產品創(chuàng)新 修建公共設施的決策依據(jù) 感恩的理由 七、邊際效用和消費者剩余理論的應用 1990年，別克（ Buick)掀起了一場大規(guī)模廣告宣傳，宣稱別克是唯一的名列前10名的美國車。以 X1, X2,… ， Xn分別表示 n種商品的數(shù)量， MU1， MU2， … ， MUn 分別表示 n種商品的邊際效用，則消費者效用最大化的均衡條件可以用公式表示為： 消費者均衡的條件 限定條件： ?????nnPMUPMUPMU?2211P1X1+ P2X2+… + PnXn=I 均衡條件： ???2211PMUPMU購買兩種商品時 P1X1+ P2X2=I 四、從基數(shù)效用到個人需求曲線 ??PMU2??設?MUP ?3263428252101????????????PQPQPQ020612252244????????????PQPQPQ0 1 2 3 4 5 6 7 6 5 4 3 2 1 P Q 邊際效用遞減快的物品，需求缺乏價格彈性和收入彈性；邊際效用遞減慢的物品一般富有價格彈性和收入彈性。 ?商品數(shù)量 總效用 邊際效用 0 0 1 10 10 2 18 8 3 24 6 4 28 4 5 30 2 6 30 0 7 28 2 甜言蜜語 和言善語 慢言細語 直言快語 豪言壯語 胡言亂語 不言不語 總效用和邊際效用曲線 0 1 2 3 4 5 6 7 Q TU U MU TU Q TU MU Q MU MU 0, TU↑ MU 0, TU↓ MU = 0, TU最大 邊際效用遞減規(guī)律 關于貨幣的邊際效用 MUm= ?（ 1）心理與生理上的原因 （ 2）物品的多用途性 a、規(guī)律的表述 b、原因 三、消費者均衡 含義： 消費者均衡 研究的是單個消費者如何把有限的貨幣收入分配在各種商品的購買中以獲得最大的效用。 dQd T UQTUMUQ)()(0lim ??????1)( ,2,1QTUMUnQ???? 如果總效用函數(shù)是多元函數(shù)，我們當假定其它商品的消費量不變，只考慮其中某一種商品消費量的微小變動引起的總效用的變動，則某商品的邊際效用就是總效