bài giảng kt vi mô chuong 4
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Bài Giảng KT Vi MôTRANSCRIPT
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Chng IV: L thuyt hnh vi ngi sn xutI. L thuyt ngi sn xut:1. Hm sn xut:1.1. Hm sn xut: xc nh sn lng ti a c th t c sn xut t bt k khi lng cho trc no ca u vo vi mt trnh cng ngh nht nh .Q max = F (L, K) ( L: labour; K : capital)u vo, u ra
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Hm sn xut ph bin nht ca cc doanh nghip l hm sn xut Cobb - Douglas c dng: Q = A.K.L (; > 0, < 1) +A l hng s , tu thuc vo n v o lng , u ra, u vo , biu th trnh cng ngh sn xut . +, l hng s cho bit tm quan trng tng i ca lao ng v vn trong qu trnh sn xut.+ Mi ngnh sn xut v cng ngh khc nhau th , khc nhau.+ , biu th hiu sut theo qui m sn xut ca hng.
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=> Vy hiu sut: l mi tng quan gia u vo v ra.* Nu: + < 1: Hm sn xut biu th hiu sut gim theo qui m ( vo tng nhiu hn u ra) + = 1: Hm sn xut biu th hiu sut khng i theo qui m. + > 1: Hm sn xut biu th hiu sut tng theo qui m (hu ht cc hng c iu ny).
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2. Sn xut trong ngn hn: (sn xut vi 1 u vo bin i)Sn xut ngn hn l khong thi gian m hng sn xut khng th thay i tt c cc u vo, c t nht l 1 u vo c nh.MPPL(Marginal physical product): l s thay i ca s lng sn phm u ra khi c s thay i ca 1 n v u vo lao ng (L). MPPL = Q/L = Q'(L)APPL: sn phm hin vt bnh qun (Average physical product): l s lng sn phm u ra tnh cho 1 n v u vo lao ng. APPL = Q/L
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K
L
Q
MPPL
APPL
1
0
0
0
0
1
1
10
10
10
1
2
21
11
10,5
1
3
31
10
10,33
1
4
39
8
9,75
1
5
42
3
8,4
1
6
42
0
7
1
7
40
-2
5,71
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Vi K khng i s lao ng tng ln (L tng) =>cho s cng nhn trn mt my gim v tng ln n mt mc no s khin cho nh xng cng khng ch, thiu my mc .. cn tr thao tc sn xut => NSL gim => Q gim => MPPL gim dn khi L tng ln do mi L tng gp thm 1 lng gim dn vo qu trnh SX. iu ny ph bin vi mi hng => cc nh kinh t khc khi qut thnh qui lut hiu sut gim dn.
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" Sn phm hin vt cn bin ca 1 u vo bin i s gim dn khi hng tng cng s dng u vo bin i ".Nguyn nhn l do khi L tng m K khng i dn n tnh trng khng hp l gia K v L khin nng sut lao ng gim dn => NSL cn bin gim dn.Ch : MPPL qua im max ca APPL v APPL = Q/L => (APPL)' = Qui lut c pht biu nh sau:
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3.Sn xut di hn (longterm production)Sn xut di hn l khong thi gian lm tt c cc u vo cu hng bin i.3.1. ng ng lng (Iso quant)M t nhng kt hp u vo khc nhau em li cng mc sn lng nh nhau* c im:MRTS (Marginal rate of technical substitution) gim dn?
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K . MPPk + L . MPPl = 0Ph bin ng ng lng c MRTS gim dn nn c hnh dng sau
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* Mt s ng ng lng c bit
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2.2. ng ng ph (iso cost)
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3. La chn kt hp u vo ti u:
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CMR: Di hn hng c kh nng ti thiu ho chi ph sn xut hn trong ngn hn (w, r khng i)
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II. Chi ph sn xut
1. Chi ph ngn hn
FC (fixed cost) l nhng chi ph khng i khi mc sn lng thay i
1.1. Ch ph c nh ch ph bin i, tng chi phVC (variable cost) l nhng chi ph thay i khi mc sn lng thay i: nguyn vt liu, nhn cng..TC (total cost) l ton b chi ph c nh v bin i sn xut ra mc sn lng. TC = FC + VC
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TC = FC + VC
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1.2. Chi ph bnh qun AFC: (Average fixed cost) AFC = FC/ Q
AVC (Average variable cost) AVC = VC/ Q ATC = AFC + AVCATC (Average total cost) ATC = TC / Q
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1.3. Chi ph c n bin (Marginal cost)L s thay i ca tng chi ph khi c s thay i cu mt n v sn lng u raMC = TC / Q = TCqMC c hnh ch U v nh hng ca qui lut hiu sut gim dn.CMR: MC i qua im cc tiu ca AVC v ATC ?
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2. Chi ph di hn (long term total cost)2.1. Tng chi ph di hn (LTC: Longterm total cost)L ton b chi ph sn xut ra mt mc sn lng nht nhQ1: TC1 = K1.r1 + L1.w1Q2: TC2 = K1.r1 + L2.w2Q2: TC2 = K2.r2 + L2.w2
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2. 2. Chi ph bnh qun di hn (LAC: (Longterm average cost)L tng chi ph di hn tnh trn mt n v u raLAC = LTC/QTrong ngn hn qui lut hiu sut gim dn chi phi nhng trong di hn chu s chi phi ca qui lut hiu sut theo qui m.
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Hiu sut tng theo qui m
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Hiu sut gim theo qui m
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Hiu sut khng i theo qui m
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a s LAC hnh ch U* Nguyn nhn:Hiu sut tng theo qui mHiu sut gim theo qui m
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2.3. Chi ph cn bin di hn( LMC: Longterm marginal cost)* Khi nim: L s thay i ca tng chi ph di hn khi c s thay i ca mt n v u raHnh dng: Tu theo hng c tnh trng hiu sut theo qui m nh th no:LMC = LTC / Q = (LTC)q
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Hiu sut tng theo qui m: LMC dc xung v nm di LAC
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Hiu sut gim theo qui m: LMC dc ln v nm trn LAC
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Hiu sut khng i theo qui m
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Khi LAC hnh ch U: LMC qua im cc tiu cu LAC
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2.4. Mi quan h gia SATC v LATC
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III. Ch ph kinh t v chi ph k ton1. Chi ph kinh t = CP tng minh + CP n* Chi ph tng (explicit):* Chi ph n (implicit):2. Chi ph k ton
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III. Li nhun1. Khi nim v cc nhn t nh hng n li nhun -Li nhun kinh t = TR - TC kt - Li nhun k ton = TR - TC kton* Cc nhn t nh hng ti li nhun LN = TR TC = P . Q ATC . Q = Q. ( P - ATC ) * Khi nim
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2. Ti a ho li nhun:* Doanh thu cn bin MR (Marginal Revenue):L s thay i ca tng doanh thu khi c s thay i camt n v u ra. MR = TR / Q = (TR)q or TRq+1 - TRqHng phi sn xut mc sn lng bao nhiu li nhun () cc i ?
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Mc sn lng ti a ho li nhun l khi Q thay i th li nhun khng thay i / Q = 0 TR - TC / Q = 0 MR = MCTi mc sn lng Q* ti MR = MC hng t li nhun cc i
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Chng V: Th trng cnh tranh v c quynI. Th trng v phn loi th trng* Khi nim th trng* Phn loi th trng* Cc tiu thc phn loi
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II. Th trng cnh tranh hon ho ( Perfect competitive market)1. c im 2. ng cu v ng doanh thu cn bin Hng chp nhn gi sn c trn th trng nn ng cu hng CTHH l ng nm ngang, ti mc gi cn bng ca th trng
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Hng bn mi sn phm mc gi Pe=> P = MR => ng doanh thu cn bin trng vi ng cu* Chng minh: Q* ti P = MC hng t li nhun ti a* Ch : iu kin c li nhun P > ATCiu kin ti a ho li nhun P = MC
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4. im ho vn, ng ca hay tip tc sn xut* im ho vnTR = TC = FC + VCP.Q = FC + AVC. QQhv = FC/(P - AVC) * im ng ca hay tip tc sn xut
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5. ng cung ca CTHH v ng cung ngnh* Hng CTHH c P = MC nn ng cung ca hng CTHH trng vi ng MC
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5. Thng d sn xut (Producer surplus)*Khi nim:
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* Mi quan h gia thng d sn xut v li nhun:PS = TR - VC = TR - ( TC -FC )=> PS = TR - TC + FC = + FC=> PS c mi quan h t l thun vi v FC
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III. Th trng c quyn (Monopoly market) 1. Khi nim 2. c im 3. Nguyn nhn: 4. ng cu v ng doanh thu cn bin
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TR = P . Q => AR = TR/Q = P
P
Q
TR
MR
AR
Nhn xt
6
0
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5
1
5
5< P
5 = P
P = MR
4
2
8
3< P
4 = P
P> MR
3
3
9
1< P
3 = P
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2
4
8
-1
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5. Quyt nh sn xut ca nh c quyn bn* Nh c quyn ti a ha li nhun ti mc sn lng Q* ti MR = MC*Gi bn P* c xc nh trn ng cu D Li nhun cc i l: max = (P* - ATC). Q*
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* Hng Q khng c ng cung hay ni cch khc khng c mi quan h hm s gia P v Qs.* Trong Q s dch chuyn ca ng cu c th lm P thay i Q gi nguyn, hoc P gi nguyn Q thay i hoc c P v Q u thay i.
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6. Sc mnh c quyn bnQ bn t P > MC=> c sc mnh Q bn Abba Lerner a ra L nm 1934 L = P - MC ; (0 < L < 1) P * Ch : - L >> => sc mnh Q cng ln - L = 0 => P = MC, khng c sc mnh Q
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7. Phn bit gi: (Price Discrimination)7.1. Phn bit gi hon ho (cp 1)
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7.2. Phn bit gi cp 2:
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7.3. Phn bit gi cp 3:MR1 =MR2 =MRtt; Q1 + Q2 = Qtt
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7.4. t gi theo thi gian (thi k)
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7.5. t gi theo thi im (cao im)
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7.6. t gi hai phn:P*CS
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IV. Th trng cnh tranh khng hon ho(Imperfect competition market)1. Cnh tranh c quyn* Khi nim: L th trng c nhiu hng cung cp v bn sn phm nhng sn phm ca mi hng c s phn bit* c im:- C nhiu ngi bn- Sn phm khc nhau (d bit ho)
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-Mi hng l ngi sn xut duy nht i vi sn phm ca mnh nn c sc mnh th trng tuy nhin L ca hng CTQ thp hn so vi Q v c nhiu hng khc sn xut cc sn phm c kh nng thay th- Vic ra nhp hay rt khi th trng l tng i d- Hnh thc cnh tranh ch yu l qung co d bit ho sn phm camnh, hu mi, ...
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* Nguyn nhn dn n c quyn:- S qui nh ca Chnh ph; v d in lc- Do iu kin t nhin cho php; Kim Bi...- Cc hng dng ln hng ro ngn cn s gia nhp ca hng khc thng qua: tnh hiu sut tng theo qui m, bng pht mnh sng ch, kim sot yu t u vo, lao ng, hay do qung co lin tc to tm l tiu dng. - S tc ng qua li gia cc hng (hp tc, cu kt); VD th trng du m CTHH=>CTQ
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* ng cu ca hng CTQ- ng cu ca hng CTQ chnh l ng cu th trng v tuy th trng c nhiu hng sx nhng cc sn phm khc nhau- ng cu ca hng CTQ dc xung t tri sang phi tuy nhin thoi hn so vi Q * Xc P*,Q*, li nhun ca hng CTQ Q* xc nh ti MR =MC, P* xc inh trn ng cu CTQ c P thp hn v Q cao hn so vi Q => L ca CTQ cng thp hn so vi Q
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* Cn bng di hn ca hng CTQ
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- Ngn hn LN>0 => hng nhp ngnh=>th phn gim => D dch chuyn sang tri tip xc LAC =>LN = 0 t cn bng di hn* So snh cn bng DN ca CTHH v CTQ+ Ging: NH c LN > 0 => cc hng nhp ngnh, cui cng t cn bng DH khi LN = 0 + Khc: CTHH cung tng S d/c sang phi, CTQ cu gim, D dch chuyn sang tri * Ch : Trong di hn hng CTQ c th phi sn xut vi cng sut tha?
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2. Th trng c quyn tp on2.1. Khi nim: L th trng ch c mt s hng sn xut v bn sn phm. Cc sn phm ging nhau gi l Q T thun tu, sn phm khc nhau gi l QT phn bit2.2. c im:- C 1 s hng trn th trng nhng c qui m rt ln
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- Cc hng ph thuc ln nhau, mt hng ra quyt nh phi cn nhc phn ng ca cc i th (phn ng nhanh qua gi hoc phn ng chm bng vic a ra s/p mi- Hng ro ra nhp rt cao nn s gia nhp ngnh l rt kh thng qua: tnh kinh t theo qui m, bn quyn hoc b cc hng c lin kt tr a
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2.3.M hnh ng cu gy khc trong th trng CTQ (The kinked demand curve model)* Cc hng QT u bit rng:+ N mt hng tng gi th cc hng cn li khng tng gi+ Nu mt hng gim gi th cc hng cn li s phi gim ga theo
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- c im c bn khi ng cu gy khc th ng doanh thu cn bin MR t qung (gin on ti mc sn lng Q*)- Sn lng t 0 => Q* hng c ng cu thoi (D1, MR1), cu co dn ln theo gi - Sn lng t Q* tr ln hng c ng cu dc (D2, MR2), cu co dn t theo giT cc c im ny nn hng QT c ng cu gy khc l kt hp ca D1v D2
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- Ti Q* MR b t qung, hay c khong trng gi l lp m chi ph cho php hng gi c gi v sn lng khi chi ph cn bin MC thay i trong lp m.- Lp m chi ph to cho cc hng QT c kh nng gi s n nh trong gi v sn lng ti u, to nn tnh cng nhc ca gi v sn lng.
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2.4. L thuyt tr chi:- Nu cc hng hp tc th s c hp ng rng buc khin h c th hoch nh nhng chin lc chung (v ngc li). - L thuyt tr chi m t nhng quyt nh thng minh nht ca cc hng ph thuc ln nhau. Nhng tr chi kinh t tin hnh mt cch hp tc hoc khng hp tc.- Nu hp tc th P cao v Q gim, li nhun tng tuy nhin thng khng chc chn, do cc hng thng ph cam kt tng li nhun cho ring mnh.
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Chng VI Th trng sc lao ngI. Cung sc lao ng1. Khi nim:
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2. Nhng nhn t nh hng n cung sc lao ng2.1. p lc v kinh t2.2. p lc v mt tm l x hi2.3. S bt buc phi lm vic2.4. Gii hn v thi gian t nhin Mt ngy ch c 24 gi = TGlv + TGnn => la chn TGlv v TGnn cho ti u *ch li cn bin ca ngh ngi: MUnn
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*Ich li cn bin ca lm vic: MUlvMUnn v MUlv cng tun theo qui lut MU gim dn t* xc nh MUlv = MClv * im xc nh thi gian lao ng ti u l im tho mn: MUlv = MClv m MClv = MUnn => t* c xc nh ti im m ch li cn bin ca lm vic bng ch li cn bin ca ngh ngi.MUlv tng => t tng, ngc li MUlv gim t gim
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MUlv = MClv m MClv = MUnn
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* Ch : V cc nhn t ni sinh v ngoi sinh (Movement along the supply curve)
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(Shift of supply curve)
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3. ng cung lao ng vng v pha sau (Backward-bending supply curve)
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II. Cu v lao ng1. Khi nim: Cu v lao ng l dn xut, th pht, pht sinh (derived demand) n ph thuc vo sn lng ca doanh nghip.
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2. Sn phm doanh thu cn bin ca lao ng: MRPl- Marginal Revenue Product of Labour* Sn phm cn bin ca lao ng (Marginal product of labour)MRPl = Q / L = QlMPl tun theo qui lut nng sut cn bin gim dn * MRPl = TR / L= MR. MPL* CTHH: MR = P => MRPL = P . MPL* Q: MR # P => MRPL = MR.MPL # P.MPL
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MRPL l mt ng dc xung t tri sang phi do qui lut hiu sut cn bin gim dn chi phi. T c im ca th trng Q c gi cao hn MC nn ng MRPl th trng Q dc hn v nm di ng MRPl trong th trng CTHH. MR= MC m P > MC => P > MR v P.MPl > MR. MPl=> cng mt mc lng th hng Q bao gi cng thu t nhn cng hn so vi hng CTHH.
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3. Nguyn tc la chn ti u trong T2 SLMRPl > W => hng nn thu thm lao ng MRPl < W => hng khng nn thu thm lao ng MRPl = W => lc ny hng t c la chn ti u trong vic thu lao ng, hng nn dng li s lng lao ng ny
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III. Cn bng trong th trng lao ngTrong th trng sc lao ng CTHH khi mt hng mun thu lao ng hng phi chp nhn mc gi tin cng sn c trn th trng. C ngha l mc tin cng c hnh thnh sn trn th trng=> ng CUNG i vi 1 hng thu lao ng trong th trng CTHH l mt ng co dn hon ton => nm ngang v song song vi trc honh) (ng cu l MRPL)
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Ti mc thu lao ng ti u L* ta c mc lng bng sn phm hin vt cn bin We = MRPl
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2. im cn bng trong T2 L phi cnh tranh2.1. Th trng c quyn mua Trong T2 ny DN l ngi thu L duy nht trn th trng nn ta c ng cu ca hng chnh l ng cu cu th trng. ng cung ca th trng cng chnh l ng cung L vi hng. * Mt s khi nim:
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Tng chi tiu ca L (Total expenditure labour)
TEl = W. L (tin cng nhn vi s lng lao ng )
Tng chi tiu ca lao ng: Total expenditure labourMEl = TE / L L s thay i tng chi tiu lao ng khi c s thay i ca mt n v u vo lao ng.
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MEl nm trn ng Sl Do Sl ch phn nh mc lng ca lao ng; cn MEl phn nh chi ph thc t phi tr khi thu thm mt l bao gm c lng v cc CP # nh bo him...L* l s L thu ti u xc nh l giao ca MEl v MRPl (=Dl)W T2 L QM bng t L* trn ng cung Sl v l mc lng W*. thp hn mc lng khi th trng lao ng l cnh tranh (xc nh bng giao ca Sl v Dl).
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Hnh minh ho xc nh L* v W* trong T2 QM
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2.2. Th trng SL Q bn (Trade Union)Mun tin cng l max , mc L (L1) xc inh ti im MR giao vi Sl, v t L1 trn ng cu Dl ta c mc lng rt cao W1.Mun ti a ho s L c thu th nghip on s chn ti im L*,W* l giao ca Sl v DlMun ti a ho doanh thu (TR max), ngha l tng tin lng l ln nht th nghip on s chn im m MR = 0, ngha l L2 v W2.
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Hnh minh ho quyt nh ca nghip on trong T2 QB
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2.3. c quyn song phng* Khi nim: c quyn song phng xy ra khi trn th trng xut hin c c quyn bn v c quyn mua sc lao ng.* c quyn bn: im A, L2 = MR x Sl, cn gi W2 xc inh trn ng cung h mong mun t c im ti u l (W2 , L2).* c quyn mua: im B, L1 =MEL x DL, mc lng W1 xc nh trn Sl, Im (W1, L1).
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Hnh minh ho Q song phng
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Nu 2 bn khng bn no c sc mnh tuyt i th mc lng s giao ng trong khong t W1 n W2. Nu sc mnh c quyn mua > c quyn bn th mc lng s gn vi W1 v ngc li nu nu c quyn mua < c quyn bn th mc lng s gn vi W2. Trong trng hp sc mnh c quyn mua v c quyn bn l ngang nhau th th trng s xc nh im ti u ti kt hp (L*, W*).
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Chng VII: S trc trc ca th trng v vai tr iu tit ca Chnh phI. S trc trc ca th trng
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1. Th trng cnh tranh khng hon ho
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- S trc trc ca th trng gy nn mt khng cho x hi (DWL: Dead weight loss)- Xut hin cc chi ph khng c li cho nn kinh t: qung co, vn ng hnh lang...2. nh hng ngoi ng (externality)* Khi no xut hin nh hng ngoi ng: khi mt hot ng tiu dng hay sn xut c tc ng i vi cc hot ng tiu dng hay sn xut khc.* C 2 loi nh hng ngoi ng:
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2.1. nh hng ngoi ng tiu cc:khi mt hot ng ca mt bn p t nhng chi ph cho mt bn khc * V d: xt nh hng ngoi ng tiu cc do nhim t vic sn xut sn tng hp (gi s y l mt ngnh sn xut trong th trng CTHH).MSC: Marginal social cost- chi ph cn bin ca x hi do c nh hng ngoi ngMEC: Marginal externality cost- chi ph cn bin ngoi ngMSC = MC + MEC
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MEC dc ln t 0 v khng sn xut khng c nh hngTi B cha tnh n MEC nn sn xut l Q2, P2; Ti A c tnh n MEC => P = MSC, sn xut Pe,Qe
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2.1. nh hng ngoi ng tch cc: Xut hin khi hot ng cu mt bn lm li cho mt bn khc * V d: hng ho cng cng, hot ng quc phng, an ninh, khu vui chi cng vin, vn hoa cng cng,..Li ch cn bin ca x hi: MSB Marginal social benefit l tng li ch m thc t XH thu c t thm mt nh trng hoa. Li ch cn bin ngoi ng: (MEB: Marginal externality benefit) l ch li thc s thu c t vic c thm mt nh na trng hoaMSB = MU + MEBCP cn bin(MC): l chi ph thm mt h gia nh trng hoa
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Ti A cha tnh n MEU sn xut ti QaTi B tnh n MEU khuyn khch tng Q t Qa=> QbTam gic ABC l nh hng ngoi ng tch cc mang li
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3. S tn ti ca hng ha cng cng (Public goods):3.1.Hng ho t nhn: L cc hng ho dch v c mua bn bnh thng trn th trng v vic tiu dng ca ngi ny loi tr vic tiu dng ca ngi khc. 2 c im l: c th loi b (excludabitity)v c th gim bt (disminishability): ct tc, ti vi...3.2. Hng ho cng cng (Public goods): Hng ho cng cng l nhng hng ho dch v m vic tiu dng ca ngi ny khng loi tr s tiu dng ca ngi khc. * V d: hot ng quc phng, bo v tng zn, cng vin...Trc trc do khng p ng c li ch ring m cho tt c Trc trc 2 gi bng 0 nn lung tiu dng l v cng ln
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* Hng ho cng cng cng gy nn mt tnh trng l s trng ch, ni vo Nh nc ca nhng k n khng, khng chu u t hoc ph hoi hay s dng lng ph cc hng ho cng cng. * v d: qui nh khng c ph hoi cy ci nhng nhiu ngi c o hoa mang v nh trng ri li Nh nc mang hoa n trng li.
=> khc phc s trc trc ny ny cn c s phi hp tp th; s hp tc gia cc c nhn v tp th c th t c cc kt qu nh mong mun. Mt x hi cng vn minh th cng c nhiu hng ho cng cng.