微觀經(jīng)濟(jì)學(xué)-微經(jīng)課件productionand

5FIRM

BEHAVIOR

AND

THEANIZATION

OF

INDUSTRYContext:

PartIIntroductionPart

II

MarketPart

III

Consumer

Behavior

and

DemandSideIn

this

part:Technical

relationship

between

input

and

output

onsupply

side

of

marketInputs

------OutputsOutputs

varies

with

inputs----production

theoryInputs

and

their

costs

varies

withoutputs----costtheory13The

Costs

of

ProductionThe

Market

Forces

of

Supplyand

DemandSupply

and

demand

are

the

two

wordsthat

economists

use

most

often.Supply

and

demand

are

the

forces

thatmake

market

economies

work.Modern

microeconomics

is

about

supply,demand,

and

market

equilibrium.WHAT

ARE

COSTS?According

to

the

Law

of

Supply:Firms

arewilling

to

produce

and

sell

agreaterty

of

a

good

when

the

price

of

the

goodis

high.This

results

in

a

supply

curve

that

slopesupward.專業(yè)用語1．生產(chǎn)（Production）2．成本（Cost）3．利潤（Profit）4.總產(chǎn)量（Total

Product,簡稱：TP）5.平均產(chǎn)量（Average

Product,簡稱：AP）6.邊際產(chǎn)量（Marginal

Product,簡稱：MP）專業(yè)用語總成本（Total

Cost，TC）固定成本(Fixed

Cost，TFC)可變成本(Variable

Cost，TVC)平均總成本(Average

Total

Cost，ATC)平均固定成本(Average

Fixed

Cost，AFC)平均可變成本(Average

Variable

Cost，AVC)邊際成本（

MarginalCost，MC)的類業(yè)主；合伙企業(yè)；公司；廠商的生產(chǎn)與成本為什么快餐食品那么快？為什么人多反而誤事？為什么它們不增加里銀幕那么多？為什么？如果你獨自經(jīng)營，那么，你必須掙

才剛好收支相抵？為什么即使你的分?jǐn)?shù)與上學(xué)期相比有所提高，你的平均積分點也有可能下降？本章和下章介紹廠商的生產(chǎn)與成本，在這里你可以找到以上問題及其他問題的答案。前一章分析了需求曲線背后的消費者行為。本章供給曲線背后的生產(chǎn)者行為。

一章中，要求你像消費者或需求者一樣思考的問題；在這一章中，你必須像生產(chǎn)者或供給者那樣思考問題。你可能覺得自己作為一個消費者更真實（因為你確實是個消費者），但你沒有

，你對生產(chǎn)者也有不少了解。你每天都處在生產(chǎn)者的包圍之中，如書店、音像商店、百貨公司、食品雜貨店、便利店、衣物干洗店、

、飯店、工廠、，以及黃頁薄和國際互聯(lián)網(wǎng)上其他無數(shù)的生產(chǎn)者。雖然你自己可能還不是一個生產(chǎn)者，但你已經(jīng)具有企業(yè)如何經(jīng)營的概念。生產(chǎn)概述1、生產(chǎn)的概念生產(chǎn)：投入、產(chǎn)出的過程。生產(chǎn)：以營利為目的、付出腦力和體力的人類活動。2、生產(chǎn)要素說兩要素說：勞動、土地；勞動、資本三要素說：勞動、土地、資本四要素說：勞動、土地、資本、企業(yè)家才能1.

Production

(13.2)Production

Function

and

Basic

ConceptsTheFunctionUsed

to

describe

relationship

between

inputs

andoutputsQ

=

f(

X1,

X2,

X3,

X4, ...

)um

output,

from

any set

of

inputsShort

runand

long

runQ=f(

X1,

X2,

X3,

X4, ...

)

,

ALL

factors

variableQ

=

f

(

X1,

X2,

X3,

X4, ...

)FIXED

IN

SR

VARIABLE

IN

SRChapter

13生產(chǎn)函數(shù)描述投入與產(chǎn)出之間的技術(shù)關(guān)系，表現(xiàn)為特定的要素投入與其獲得的最大產(chǎn)出量之間的關(guān)系。著名的生產(chǎn)函數(shù)：C

D函數(shù)Q

f(L,K)Q

A

Lα

K

1

α其中：A-技術(shù)進(jìn)步L-勞動

K-資本勞動的投入產(chǎn)出彈性生產(chǎn)要素投入勞動土地資本企業(yè)家才能產(chǎn)出物品勞務(wù)廠商生產(chǎn)函數(shù)在一定的生產(chǎn)技術(shù)水平下，生產(chǎn)要素投入量與最大產(chǎn)出量之間的物質(zhì)數(shù)量關(guān)系Q=

f（L

,

K）生產(chǎn)函數(shù)概述PRODUCTION

AND

COSTSThe

Production

Function–

The

production

function

shows

thety

ofinputsusedty

ofoutput

ofrelationship

betweento

make

a

good

and

thethatgood.1.1.2

SomeParticular

Production

FunctionsA

function

is

homogeneous

of

degree-n,

ifmultiplying

all

inputs

by

λ,

increases

the

dependentvariable

by

λn.Q

=

f(

K,

L)So, f(

λK,

λL)=

λQA

Useful

Specific

function:

Cobb-DouglasProductionQ

=

A

?

Kα

?

L1-αCobb-Douglas

Production

Functions

arehomogeneous

of

degree

1

in

this

case.Q

=

f

(

K,

L)

for

two

input

case1.1.4

Time

Horizon

in

ProductionShortrun---- riod

that

at

least

one

inputcan

change

while

at

least

another

input

donot

have

enough

time

to

change.Long

run---- riod

long

enough

for

allinputs

to

change

as

producers

please.The

very

long

run----In

addition

to

inputs,technology

changes短期生產(chǎn)函數(shù)（勞動可變）短期生產(chǎn)函數(shù)：K不變，Ｌ可變，則與產(chǎn)量有關(guān)的幾個概念總產(chǎn)量平均產(chǎn)量邊際產(chǎn)量Q

=

F

(

L,K

)LAP =

F

(

L,K

)/

LTPL

=

F

(

L,K

)MPL

=

TPL/

LMPL

=

dTPL/

dLTP

、AP

與MP短期生產(chǎn)函數(shù)Q

=

f（L

,

K0）TPAPMP總產(chǎn)量企業(yè)在一定時期內(nèi)生產(chǎn)的全部產(chǎn)量TP

=

Q

=

f（L）平均產(chǎn)量平均每單位變動投入生產(chǎn)的產(chǎn)量APL

=

TP/L邊際產(chǎn)量每增加一單位變動投入所增加的產(chǎn)量MPL

=

dTP/dL三種產(chǎn)量的關(guān)系Marginal

Product–

The

marginal

productof

any

input

in

theproduction

process

isthe

increase

in

outputthat

arises

from

an

additional

unit

of

that

input.The

Production

FunctionDiminishing

Marginal

ProductDiminishing

marginal

product

is

the

propertywherebythe

marginal

product

of

an

inputdeclines

asthe ty

of

the

input

increases.Example:

As

more

and

more

workers

are

hired

atafirm,

each

additional

worker

contributes

lessandless

to

production

because

the

firm

has

a

limitedamount

ofequipment.Figure

2

Hungry

Helen’s

Production

FunctionCopyright

?

2004

South-Western(ty

ofOutputsper

hour)150140130120110100908070605040302010012345Number

of

Workers

HiredProduction

functionDiminishing

Marginal

ProductThe

slope

of

the

production

functionmeasures

the

marginal

product

of

an

input,such

as

a

worker.When

the

marginal

product

declines,

theproduction

function es

flatter.1.1.3

Basic

Product

ConceptsAverage

Product

=

Q

/

Loutput

per

labor,

which

is

variableMarginal

Product

=

△

Q/

△

L

=

dQ/dLoutput

attributable

to

last

unit

of

labor

appliedTotal

ProductL01202463702449222511018221.2

Short-Run

Production:

Law

of

DiminishingReturnLMarginal

ProductAverageProduct12

3

4

5LQM

PAP00------12020202345467092110262422182323.332322Think

about

average

grade

of

whole

theclass

and

grade

of

new

entrants.Delta

EpsilonGrade808010084Average

90Alpha

Beta

Gama90

80

7085

80LTotal

OutputMarginalProductLAverageProductInflectionpointHow

outputs

changes

with

changes

in

one

input?When

MP

>

AP,

then

AP

is

RISING–

If

your

marginal

grade

in

this

class

is

higher

thanyour

average

grade

point

average,

then

yourG.P.A.

Is

risingWhen

MP

<

AP,

then

AP

is

FALLINGIf

the

marginal

weightadded

to

a

team

is

less

thanthe

average

weight,

the age

team

weightdeclinesWhen

MP

=

AP,

then

AP

is

at

its

MAXIf

the

new

hire

is

just

as

efficient

as

the

averageemployee,

the age

productivity

doesn’tchange一種可變投入品生產(chǎn)函數(shù)假定兩種投入中，資本固定，僅勞動可變，其生產(chǎn)函數(shù)如下表4567891其中，勞動平均產(chǎn)出（ALP）到4以后下降；勞動邊際產(chǎn)出從第3個以后下降。注意生產(chǎn)函數(shù)是在給定知識和技術(shù)條件下成立的。理解為“在一定技術(shù)條件下特定的投入品組合有效使用帶來的最大的可能性產(chǎn)出”。隨著知識技術(shù)不斷進(jìn)步，生產(chǎn)函數(shù)會發(fā)生變化。一種可變投入品生產(chǎn)函數(shù)：幾何圖形表達(dá)總產(chǎn)出曲線上某勞動投入數(shù)量點的勞動平均產(chǎn)出是該點與原點連線射線的斜率。B點與原點斜率為60/3=20。某勞動投入量的邊際產(chǎn)出是總產(chǎn)出曲線上過該點切線的斜率。B點前后先升后降。D點的切線斜率為零，總產(chǎn)出最大。當(dāng)邊際產(chǎn)出高于平均產(chǎn)出時，平均產(chǎn)出上升；反之下降；邊際產(chǎn)出在平均產(chǎn)出的最高點處從上到下穿01234

567

8901210ABC60112102030每月產(chǎn)量每月產(chǎn)量E總產(chǎn)量平均產(chǎn)量邊際產(chǎn)

量3

4

5

6

7

8

9D10

每月投入勞動每月投入勞動短期產(chǎn)量曲線（勞動可變）APTPMPQLTPLOAPMPLOL1

L2

L3L1

L2

L3MPTPAPT

P

與

M

P斜

率

邊

際拐

點

頂

點頂

點

零

點T

P

與

A

P射

線

平

均M

P

與

A

PMP>AP

AP遞增MP=AP

AP最大MP<AP

AP遞減Law

of

Diminishing

ReturnsINCREASES

IN

ONE

FACTOR

OF

PRODUCTION,HOLDING

ONE

OR

OTHER

FACTORS

FIXED,AFTER

SOME

POINT,MARGINAL

PRODUCT

DIMINISHES.A

SHORTRUN

LAWpointofdiminishingreturnsVariable

inputMPButalsoholdfor

longrun

when

factorproportion

changes邊際

遞減規(guī)律含義：當(dāng)兩種要素結(jié)合生產(chǎn)一種產(chǎn)品時，若技術(shù)水平和其他要素投入固定不變，只有一種要素投入變動，隨著該可變要素投入的增加，其邊際產(chǎn)量減少原因：不變投入和可變投入的組合比例變化，比如技術(shù)一定，生產(chǎn)要間有一個最佳的配比。理解注意幾點：收益遞減規(guī)律具有獨立于經(jīng)濟(jì)制度或其它社會條件而發(fā)生作用的普遍性或一般性。邊際收益遞減規(guī)律作用前提之一“技術(shù)水平”不變，它不否認(rèn)技術(shù)條件變化可能導(dǎo)致勞動生產(chǎn)率提高。規(guī)律表述有“最終”二字修飾條件。也就是說，某一投入邊際收益并非自始至終遞減，它有可能在一定范圍內(nèi)呈現(xiàn)增加趨勢。邊際遞減舉例：和尚吃水第一個階段，平均產(chǎn)出遞增，因為生產(chǎn)的規(guī)模效益正在表現(xiàn)出來；（一個和尚挑水吃）第二個階段，平均產(chǎn)出遞減，總產(chǎn)出增長的速度放慢；（二個和尚抬水吃）第三個階段，邊際產(chǎn)出為負(fù)，總產(chǎn)出絕對下降。（三個和尚沒水吃，減員增效）生產(chǎn)合理區(qū)域在第二個階段。0EⅠFQTPⅡ

ⅢAPLMPQL0ABⅠⅡⅢTPFMP>APAPMP<APAPMP<0TPMP=APAP最大EAPMP=0TP最大生產(chǎn)階段的劃分APMPLOL2

L3APMPI

II

III平均產(chǎn)量遞減邊際產(chǎn)量為正平均產(chǎn)量遞增邊際產(chǎn)量為負(fù)理性廠商選擇第II階段兩種可變投入情況與等產(chǎn)量線：長期假定“勞動和資本兩種投入都可以變化”代表了經(jīng)濟(jì)分析的長期情況，而“長期”和“短期”是經(jīng)濟(jì)學(xué)分析方法中兩個極為重要的概念，與日常語義具有不同含義。

用短期和長期來表示微觀經(jīng)濟(jì)主體調(diào)節(jié)行為受限制程度不同的兩類時間條件：短期表示受到限制較小，因而調(diào)節(jié)時間較短，如廠商對于勞動，原料投入數(shù)量的調(diào)節(jié)等屬于短期問題；長期則指調(diào)節(jié)受到的限制較大，因而需要調(diào)節(jié)時間較長，如通過固定資本投資來改變企業(yè)最大產(chǎn)出能力。不 業(yè)不同企業(yè)的“長期”對應(yīng)的具體時間長度有顯著差別。長期生產(chǎn)函數(shù)Q

=

F

(

L,

K

)L，K均可變，并可互相替代問題：企業(yè)如何確定L，K的組合比例？等產(chǎn)量線等成本線最優(yōu)要素組合長期生產(chǎn)函數(shù)：表

方式投入要素都發(fā)生變化的情況下，所謂長期生產(chǎn)函數(shù)的表

表示：勞動投入資本投入12345120405565852406075859035575901001054658510011011557590105115120表中數(shù)據(jù)表示不同勞動與資本投入量組合能夠提供的最大產(chǎn)出量（即技術(shù)上最有效率的產(chǎn)出量）。從橫向看，在資本投入量固定時產(chǎn)出隨著勞動投入增加而增加；從縱向看，在勞動投入量固定時產(chǎn)出隨著資本動投入增加而增加。長期生產(chǎn)函數(shù)：模型方式每年投入資本表 數(shù)據(jù)的幾何表達(dá)：等產(chǎn)量曲線（注意：直接描圖得到的是不平滑圖形，平滑處理是假定了投入品無限細(xì)分的可能性）。等產(chǎn)量線Q1表示獲得55個產(chǎn)出的投入品組合的集合：A點表示1單位勞動與3單位資本組合可以得到

55單位產(chǎn)出，D點則表示3單位勞動與1單位資本組合同樣可以得到55單位產(chǎn)出。Q2與Q3則分別表示獲得75個和90個產(chǎn)出的投入品組合的集合。

Q2位于Q1的右上方，表示如果要生產(chǎn)

的產(chǎn)量，必須投入

的勞動或（和）資本。等產(chǎn)量線的集合又稱作等產(chǎn)量圖，它描述了企業(yè)的

1生產(chǎn)函數(shù)，即通過采用一定技術(shù)和不同投入品組合來獲得不同數(shù)量的產(chǎn)出。每年投入勞動0123452345Q2=75Q1=55Q3=90ABCDE等產(chǎn)量曲線概念1、等產(chǎn)量線（1）概念:生產(chǎn)某一特定產(chǎn)量的不同生產(chǎn)要素組合點的集合。Q

f

(L,K)L、K均是可變要素等產(chǎn)量線上不同的生產(chǎn)要素組合所生產(chǎn)的產(chǎn)量沒有區(qū)別。等

產(chǎn)

量

曲

線技術(shù)水平不變的條件下，生產(chǎn)同一產(chǎn)量水平所使用的兩種要素各種組合的軌跡KLOQ3Q2Q1等產(chǎn)量線特征斜率一段為負(fù)，兩段為正。等產(chǎn)量線有無數(shù)條，越遠(yuǎn)離原點產(chǎn)量越高。任何兩條等產(chǎn)量線不相交。凸向原點。LOQ1K1K2L1

L2⊿K⊿LMRTSLK⊿L=

-

⊿K

dKdLMRTSLK

=

-LKMRTS

=MPLMPK邊際技術(shù)替代率在技術(shù)和產(chǎn)量不變的條件下，增加一單位某種要素的投入所能減少的另一種要素的投入量勞動替代資本的邊際技術(shù)替代率K邊際技術(shù)替代率的變化趨勢邊際技術(shù)替代率：經(jīng)濟(jì)含義和數(shù)學(xué)表達(dá)等產(chǎn)量線的斜率表示在保持產(chǎn)出不變前提下一種投入品與另一種投入品的替代關(guān)系，即：MRTS

=

- K

/ L

。如果用數(shù)學(xué)推導(dǎo)，可以發(fā)現(xiàn)MRTS是兩種投入品邊際產(chǎn)量的比率：如果生產(chǎn)函數(shù)是Q=f(x1,x2)則MRTS=-d

x2

/d

x1

(條件是Q保持不變）。依據(jù)全微分公式：dQ=Q/x1(dx1)+Q/x2(dx2)由于產(chǎn)量不變即dQ=0，∴

Q/

x1(

dx1)

+

Q/x2(

dx2)

=

0

；dx2

/dx1

=

-

Q/x1

/(

Q/x2)∵

Q/x1

和

Q/x2

分別是兩種要素的邊際產(chǎn)品∴dx2/dx1

=

-

MP1

/

MP2；即MRTS是兩種投入品邊際產(chǎn)量的比率。邊際技術(shù)替代率遞減性質(zhì)等產(chǎn)量線凸向原點，幾何含義表示曲線從左到右的斜率絕對值越變越小。即邊際技術(shù)替代率越變越小.右圖表示，產(chǎn)出為75等產(chǎn)量線的

MRTS從2減少到1，到2/3，再到

1/3。MRTS遞減性質(zhì)的經(jīng)濟(jì)含義是，當(dāng)大量使用勞動來替代資本時，勞動的生產(chǎn)率會下降；同樣，大量使用資本來替代勞動時，資本的生產(chǎn)率會下降；因而，生產(chǎn)過程應(yīng)“平衡”和“適當(dāng)”地利用勞動和資本。每月投入資本每月投入勞動012345123451Q

=75Q2=90K=1/3L=1L=1L=1K=2K=1L=1K=2/3等成本線圖形：要素價 既定的條件下，花費一定成本所能夠 的兩種要素最大數(shù)量組合的軌跡OLC0rC0w問題：等成本線的斜率等成本線位置的決定等成本線位置的變動概念：在生產(chǎn)經(jīng)費及生產(chǎn)要素價

即定的情況下，生產(chǎn)者所能到的最大的各種要素的組合。K數(shù)學(xué)公式：C0

=wL+rK等成本線的變動LKKL總成本增加或減少工資增加或減少生產(chǎn)要素的最優(yōu)組合最小成本最大產(chǎn)量成本既定產(chǎn)量最大

產(chǎn)量既定成本最小KOLAQ3Q2Q1BCD-dK/

dL

>

w

/rMPL/MPK

=

w/r生產(chǎn)者均衡（1）概念：生產(chǎn)者均衡點是指生產(chǎn)者在現(xiàn)有生產(chǎn)經(jīng)費、生產(chǎn)要素價及技術(shù)水平的約束下，追求到最大的產(chǎn)量。（2）生產(chǎn)者均衡點的位置：等產(chǎn)量線與等成本線的相切點。生產(chǎn)者均衡點K0LK*L*E0M/PKM/PL等成本線等產(chǎn)量線生產(chǎn)者均衡的理解產(chǎn)量最大化條件PL.K+PK.K=MMPK

MPLPK

PLK②0LE0K*L*●M/PLM/PK等成本線的斜率為：推導(dǎo)式②：等產(chǎn)量線的斜率為：MRTS

K

MPLL

MPKPK

PL∵在均衡點有PKMPKMP

P

L

L∴PK

PLMPK

MPL已知：生產(chǎn)者均衡點的變動（1）0LE0●1、生產(chǎn)經(jīng)費增加等成本線水平右移M→M′=M+△MKM/

PKM′/

PLM′/PKM/PLE1●PL.L+PK.K=M′生產(chǎn)擴(kuò)展線生產(chǎn)者均衡點的變動（2）0E1E0●LM/

PL

′M/PL2、要素的價

變動，等成本線旋轉(zhuǎn)?！逷L→PL′∴等成本線斜率變化=-PL′/PKKPL′.L+PK.K=MM/PK生

產(chǎn)

擴(kuò)

展

線KLQ1Q3Q2S1S2等斜線等產(chǎn)量曲線上邊際技術(shù)替代率相等的點的軌跡OKLOQ2Q1Q3LTC擴(kuò)展線由成本變動引起的最優(yōu)要素組合變動的軌跡脊線與生產(chǎn)經(jīng)濟(jì)區(qū)域KLOQ3KMP

<0AQ2Q1

MPL<0脊線B脊線生產(chǎn)的經(jīng)濟(jì)區(qū)域脊線等產(chǎn)量線上斜率為0的點或者斜率為∞的點與原點的連線生產(chǎn)的經(jīng)濟(jì)區(qū)域兩條脊線所圍的區(qū)域脊線的理解(1)KLABC·D·50100150C點是等產(chǎn)量曲線上斜率為正的弧段上的一點,卻在脊線之外，與D點比較，C點需要

的資本、

的勞動，由于資本和勞動的價

不可能為負(fù)，這樣企業(yè)在D點經(jīng)營一定比在C點經(jīng)營更便宜。脊線的理解（2）脊線的概念：由等產(chǎn)量線上斜率為零及斜率無窮大的點所構(gòu)成的區(qū)域脊線所含區(qū)域等產(chǎn)量線斜率為負(fù)，是生產(chǎn)合理投入的區(qū)域（經(jīng)濟(jì)區(qū)域）。在合理投入?yún)^(qū)AOB內(nèi)：MPL>0；MPK>0即：K,L;L,K稱為有效替代。LL1K1OKA●●●●●●●●●●B●規(guī)模與長期生產(chǎn)函數(shù)600500400300200100700規(guī)模所有要素投入同時、同方向、同幅度變動時引起的產(chǎn)量變動KLO規(guī)模 遞增：

產(chǎn)量的增加幅度大于要素的增加幅度規(guī)模 不變：

產(chǎn)量的增加幅度等于要素的增加幅度規(guī)模 遞減：

產(chǎn)量的增加幅度小于要素的增加幅度長期生產(chǎn)函數(shù)Long

Run

Production:

Returns

to

ScaleScale

Changes

and

Returns

to

ScaleWe

call

it

scale

changes

that

all

inputs

changeinabout

the

same

proportionReturns

to

scale

refer

to

changes

in

output

resultingfrom

changes

in

all

inputsThree

Kinds

of

Returns

to

ScaleConstant

Returns

To

Scale

(CRS)doubling

of

all

inputs

doubles

outputIncreasing

Returns

To

Scale

(IRS)doubling

of

all

inputs

MORE

than

doubles

outputDecreasing

Returns

To

Scale

(DRS)doubling

of

all

inputs

DOESN’T

QUITE

doubleoutput1.3.3

Cobb-Douglas

Production

Function

andReturns

to

ScaleQ

=

A

?

Kα?Lβ

is

aCobb-DouglasProduction

FunctionIMPLIES:Can

be

IRS,

DRS

orCRS:if

α+β=1,

thenCRSif

α+β

<

1,

then

DRSif

α+β

>

1,

then

IRS1.3.4

ReasonforReturns

to

ScaleIncreasing

Return

to

Scale:Product-specific

economiesspecializationPlant-specific

economiesIndivisibility of

Lumpy

EquipmentEconomies

in

overheadEconomies

in

required

reserves

and

investment(maintenance)economies

of

scope

(interactions

among

products).Firm-specific

economieseconomies

indistribution

and

transportation

of

ageographically

dispersed

firm,

or

economies

in

marketing,sales

promotion,

or

R&D

of

multi-product

firms.Decreasing

Return

to

ScaleProblems

of

coordination

and

control

as

it

ishard

to

send

and

receive

information

as

the

scalerises.Other

disadvantages

of

large

size:slow

decision

ladderInflexibility1.3.5

Trend

of

Return

to

ScaleIRS ,

and

thenCRS,

andDRS

finally1.4

The

Very

Long

Run:

Technological

ChangesTechnological

changes

alter

production

functionsGiven

inputs

can

produce

more

outputs2002

South-WesternPublishing2.

CostThe

meaning

and

measurement

of

costShort-run

Cost

FunctionsLong-run

Cost

FunctionsLinks

between

Cost

and

ProductionScale

Economies

and

CostWHAT

ARE

COSTS?According

to

the

Law

of

Supply:Firms

arewilling

to

produce

and

sell

agreaterty

of

a

good

when

the

price

of

the

goodis

high.This

results

in

a

supply

curve

that

slopesupward.WHAT

ARE

COSTS?The

Firm’s

Objective–

The

economic

goal

of

the

firm

is

toprofits.izeTotal

RevenueThe

amount

a

firm

receivesfor

the

sale

of

itsoutput.Total

CostThemarket

value

of

the

inputs

afirm

usesinproduction.Profit

is

the

firm’s

total

revenue

minus

itstotal

cost.Profit

=

Total

revenue

-

Total

costA

firm’s

cost

of

production

includes

all

theopportunity

costs

of

making

its

output

ofgoods

and

services.Explicit

and

Implicit

CostsA

firm’s

cost

of

production

includeexplicitcosts

and

implicit

costs.Explicit

costs

are

input

costs

that

require

a

directoutlay

of

money

by

thefirm.Implicit

costs

are

input

costs

that

do

not

require

anoutlay

of

money

by

thefirm.商為提供一定量的某種產(chǎn)品或服務(wù)所實際花費的生產(chǎn)要素的價值成本廠商或租用要素的花費顯性成本隱性成本廠商自身擁有的并投入到生產(chǎn)中的要素價值成本機(jī)會成本的含義機(jī)會成本是經(jīng)濟(jì)學(xué)中最具有閃光點的思想之一，它與資源的稀缺和資源的多種用途相聯(lián)系。為了獲得某種產(chǎn)品，必須放棄什么?當(dāng)一種資源投入某一用途以后，就失去了作為

的可能性。其它諸用途中的最大收益就是資源投入該用途的機(jī)會成本。機(jī)會成本是從社會角度來看有限資源用于某一經(jīng)濟(jì)活動的代價。但放棄的用途難于窮盡，獲利也有很大的不確定，所以機(jī)會成本的計算是的。它對于經(jīng)濟(jì)決策是至關(guān)重要的。讀大學(xué)、讀

的機(jī)會成本是多少呢?Economists

measure

a

firm’s

economicprofit

as

total

revenue

minus

total

cost,including

both

explicit

and

implicit

costs.Accountants

measure

the

accounting

profitas

the

firm’s

total

revenue

minus

only

thefirm’s

explicit

costs.When

total

revenue

exceeds

both

explicitand

implicit

costs,

the

firm

earns

economicprofit.–

Economic

profit

is

smaller

than

accountingprofit.Figure

1

Economic

versus

AccountantsCopyright

?

2004

South-WesternRevenueTotalopportunitycostsHow

an

EconomistViews

a

FirmHow

an

AccountantViews

a

FirmRevenueEconomicprofitImplicitcostsExplicitcostsExplicitcostsAccountingprofitTable

1

A

Production

Function

and

Total

Cost:Hungry

Helen’s

FactoryCopyright?2004

South-Western2.1

Meaning

of

Cost in

Economics

(13.1)There

Are

Many

Economic

Cost

Concepts2.1.1

Various

Cost

Conception

Relevant

to

Economic

CostOpportunity

Cost

--

value

of

next

best

alternative

use.Explicit

vs.

Implicit

Cost

--actual

prices

paid

vs.opportunity

cost

ofowner d

resources.

(Value

of

one’sown

resources)Accounting

Cost

—Actual

paymentSunk

Costs

--

already

paidfor, or

there

is

already

acontractual

obligationto pay

but

cannot

be

recovered.It

isirrelevant

in

decision

making.Cost

ItemActualExpenditureValue

NowMeat

and

vegetables500500Kitchen

appliances1000500Waitress

hour10001000Decoration20000Utilities500500In

sum50002500Own

effort2000Service

of

familymember1000Ownhouse500TOTAL500060002.1.2

Understand

Cost

as

an

EconomistWhendo

you

start ng

the

business?,

we

do

not

consider

opportunity

costs

(

the

explicit

costs

are5000

instead

of

2500)Revenue:

4000？8000？9000？

or

more?Second,

we

do

not

consider

the

difference

between

explicit

costsand

implicit

costs

(Suppose

no

implicit

costs)

:Revenue:

2000？3000？5500？or

more?Third,

when

will

you

run

the

business

if

all

cost

consideredRevenue:

3000？5500？6500？8000？9000？CostsActual

PaymentsOpportunityCosts(Accounting

Costs)Explicit

Cost50002500Implicit

CostNA3500In

Total500060002.1.3

How

economists

measure

a

variety

of

Costs?Depreciation

Cost

Measurement.

Accounting

depreciation(e.g.,

straight-line

depreciation)

tendsto

have

littlerelationship

with

the

actual

loss

of

valueTo

an

economist,

the

actual

loss

of

value

isthe

true

cost

ofusing

machinery.Inventory

Valuation.

Accounting

valuation

depends

on

itsacquisition

costEconomists

view

the

cost

of

inventory

asthe

cost

ofreplacement.–Unutilized

Facilities.

Empty

space

may

appear

to

have"nocost”Economists

view

itsalternative

use

(e.g.,

rentalvalue)

asits

opportunity

cost.2.1.4

Measures

of

Profitability

andDecisionAccountants

and

economists

view

profitdifferently.Accounting

profit,

at

its

simplest,

is

revenuesminus

explicit

costs.Economists

include

other

implicit

costs

(suchas

a

normal

profit

on

investedcapital).Economic

Profit

=

Total

Revenues

-

ExplicitCosts

-

Implicit

CostsAll

Costs

are

understood

as

opportunity

costShoreham

Power

Plant

in

LongIslandCostRevenuecategoriesvalueSituation

1Situation

2Initialexpenditure1.5

billionSunk

cost1

billionIncrementalcost

if

run

it0.6billion0.7billion1.2billion1972Plan

as

ofExpectation

of

futureMarket

Share

of

Titanium

Dixiode34%33%33%Dupont National

Lead Another

SevenMarket

Share

of

Titanium

Dixiode18%18%64%Dupont National

Lead Another

SevenNew

regulation;Rising

price

of

materials;Growing

demandPotential

RivalStay

outsideEnterDupont’sStrategyMaintainhigh

priceDupont：100Rival：0Dupont

：60Rival

：40Price

cutDupont

：50Rival：0Dupont：50Rival

：-5Dupont’s

Threat

as

a

StrategyPotential

RivalStay

outsideEnterDupont’sStrategyMaintainhigh

priceDupont：100Rival：0Dupont

：10Rival

：40PricecutDupont

：50Rival

：0Dupont：20Rival

：-5Examples

of

Sunk

CostConduct

a

desperate

fight

(throw

away

the

scabbard

)Mao’s

CourageBlind

knightOuting

Decision

with

yourown

car

vs.

with

rented

carAirfare

discountCourage

of

a

man

suffering incurable

diseaseFootball

ticket

or

movieWhat

is

the

true

cost

of

attending

this

course?Sellrefrigerator和會計師的區(qū)別利潤概念有差別根據(jù)利潤是正還是負(fù)決定是否營業(yè)會計師要比較不同項目的利潤和會計師決策的結(jié)果是一樣的，只是用到的工具不同和會計師在租房決策上的區(qū)別：已經(jīng)租房簽約一年，月租500元；到第五月時，租房者欲長期離開

，決定轉(zhuǎn)租，此時市場

上升至700元。一位同學(xué)愿意花600元租房。會計師：(1)出租給該同學(xué)，(會計)利潤為100元；(2)出租給他人，(會計)利潤為200元。不租給該同學(xué)。：(1)出租的機(jī)會成本為700元；(2)出租給該同學(xué)的收益為

600元。經(jīng)濟(jì)利潤為－100，不租給該同學(xué)。return2.1.5

SummaryEconomic

cost

=

explicitcost

+

implicit

costBoth

explicit

and

implicit

cost

are

measured

byopportunity

costSunk

cost

is

excluded

from

economiccostIn

economic

cost

is

included

normal

profitNormal

profit

isunderstood

opportunity

cost

of

runningthe

business

project

or

investment

programThe

lowest

cost

of

different

possibilities

(a

technicalconcept)2.2.

Short

Run

Costs

(13.3)2.2.1

Various

Short

Run

CostsTC

=

FC

+

VC fixed

&

variable

costsATC

=

AFC

+

AVC

=

FC/Q

+

VC/QMC

=△C/

△

QcalculationcompositionTotalAverageMarginalFixedFCAFCNot

availableVariableVCAVCMCAdditionTCATCMC短期成本函數(shù)1.總成本：產(chǎn)某一既定產(chǎn)量的總成本等于生產(chǎn)過程中所使用的每一種投入要素成本之和。TC=TFC+TVC

總固定成本+總變動成本2.固定成本：短期生產(chǎn)過程中所有固定不變的投入要素的成本，是不隨產(chǎn)量變化的常數(shù)。短期平均成本和邊際成本1.平均總成本：ATC=TC/Q2.平均固定成本：AFC=FC/Q3.平均變動成本：AVC=VC/Q4.邊際成本：MC=TC/Q=VC/Q對于

續(xù)的TC函數(shù)：MC

=

d(TC)/dQ

=

d(VC)/dQ2.2.2

Short

Run

Cost

GraphsAFCQ1.Q2.AVCMC

intersects

lowest

pointof

AVC

and

lowest

point

ofATC.When

MC

<

AVC,

AVCdeclinesWhen

MC

>

AVC,

AVC

risesJust

think

about

your

grade

in

school3.QAFCATCAVCMC2.2.3

Relation

of

Cost

&

Production

Functions

inSRThe

reason

for

costs

changes:Law

of

diminishing

marginal

returnAP

&

AVC

are

inversely

related.(ex: oneinput)AVC

=

WL

/Q

=

W/

(Q/L)

=

W/

APL–

As

APL

rises,

AVC

fallsMP

and

MC

are

inversely

relatedMC

=△

TC/

△

Q=W△

L/△Q=W/(△Q/△L)

=

W

/

MPL–

As

MPL

declines,

MC

risesproduction

functionsMPLAPcost

functionsMCAVCThe

relationship

between

the ty

afirm

can

produce

and

its

costs

determinespricing

decisions.The

total-cost

curve

shows

thisrelationship

graphically.Table

1

A

Production

Function

and

Total

Cost:Hungry

Helen’s

FactoryCopyright?2004

South-WesternFigure

3

Hungry

Helen’sTotal-Cost

CurveTotalCost$8070605040302010ty(of

Outputs

per

hour)Copyright

?

2004

South-Western0

10 20

30

40

50 60

70Total-costcurveTHE

VARIOUS

MEASURES

OFCOSTCosts

of

production

may

be

divided

intofixed

costs

and

variable

costs.Fixed

costs

are

those

costs

that

do

not

vary

with

the ty

of

output

produced.Variable

costs

are

those

costs

that

do

vary

with

the ty

of

output

produced.Total

CostsTotal

Fixed

Costs

(TFC)Total

Variable

Costs

(TVC)Total

Costs

(TC)TC

=

TFC

+

TVC短期成本曲線Average

CostsAverage

costs

can

be

determined

by

dividingthe

firm’s

costs

by

the ty

ofoutput

itproduces.The

average

cost

is

the

cost

of

each

typicalunit

ofproduct.Average

CostsAverage

Fixed

Costs

(AFC)Average

Variable

Costs

(AVC)Average

Total

Costs

(ATC)ATC

=

AFC

+

AVCAFC

Fixed

cost

FCty

QAVC

Variable

cost

VCty

QATC

Total

cost

TCty

QMarginal

CostMarginal

cost

(MC)

measures

the

increaseintotal

cost

thatarises

from

an

extra

unitofproduction.Marginal

cost

helps

answerthefollowingquestion:How

much

does

itcost

to

produce

an

additionalunit

of

output?MC

(change

in

total

cost)

TC(change

in

ty)

QMarginal

Cost

Thirsty

Thelma’s

LemonadeStandtyTotalCostMarginalCosttyTotalCostMarginalCost0$3.00—13.30$0.306$7.80$1.3023.800.5079.301.5034.500.70811.001.7045.400.90912.901.9056.501.101015.002.10Total

Cost$15.0014.0013.0012.0011.0010.009.008.007.006.005.004.003.002.001.00tyof

Output(glasses

of

lemonade

per

hour)0Total-cost

curveCosts$3.503.253.002.752.502.252.001.751.501.251.000.750.500.25tyofOutput(glasses

of

lemonade

per

hour)0MCATCAVCAFCMarginal

cost

rises

with

the

amount

ofoutput

produced.–

This

reflects

the

property

of

diminishingmarginal

product.Costs$3.503.253.002.752.502.252.001.751.501.251.000.750.500.25tyofOutput(glasses

of

lemonade

per

hour)0MCThe

average

total-cost

curve

is

U-sh

d.At

very

low

levels

of

output

average

totalcost

is

high

because

fixed

cost

is

spreadover

only

a

few

units.Average

total

cost

declines

as

outputincreases.Average

total

cost

starts

rising

becauseaverage

variable

cost

rises

substantially.The

bottom

of

the

U-sh d

ATC

curveoccurs

at

the

ty

that

minimizesaverage

t