MATH 204 Exam 2, Fall 2002
American University of Beirut · Mathematics for Social Sciences II · 3 pages
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LEBRARY
GE HA GHE
Nov. 9,2002
‘ ( 8 9 10
instructions:
1. Write your name and circle your section number. a
2 Answer,in detail, every part in the space provided for it and circle your final result .Do not
mention just the answer. neh + Saye 4,
3.The colored booklet is for scratch work and will not be corrected. Sm, 4 fxg % .
1. The solution to a system of equations b ving the form AX = B can be found ia the matrix
A
7 60
multiplication: =X “(3 mh 24 ohh V1 a AY. ao
1.(10%) What is the original system of equations? : e bs.
‘ Ve Ga Ht Ves we briny Hae vest ue ws
Ak=6 Ais C4 6) eat He invesse M
MH ef ach. a Ke ~) Doe UR ya. Be Ousich AZ = (on za )er
K
Nowseess ye fa@ FT)... Ma ny phoned ours, AK s#
i (As 9/ a)" 4 “ val
.(5%) What is the solution ?
So Ny Xs
“e (sey) 0 xb 7 u
I.(10%) The following matrix gives the transition probabilities related to a nfarket dominated by
two firms, A and B:
rs 0.4 0.6
0.2 08
Assume currently firm Ahas 65% of the market share.
1.(5%) Predict the market share of A in the next period. a
y » fort a les Orit, Oe ats ) _
a ose —“
, poe
fe sf , yo eee Poe
: - Govt :
Cob Re yt ee uo) 2 SS { . (0 ha rs . _ -
iy ‘a if ; oe rae
Ke? bo! y 4 \ ¥
2:{40%) Assume the transition matrix remains stable, Find the expected equilibrium shares of
thet two firms, if they exist.
peck YN UNIVERSITY
Pp LIBRARY
OF BEIRUT
‘ -5 1 -2
Ill.(20%)Given the matrix 4=|-4 0 -2
3-2 -3
1.Calculate || by adding columns. Show your work.
. -5S |
3 45 = (co —6-16)~(¢ -Qo +12)
3| 3-9 — 22 +8 =\-147]
wa
x, 28
2. Use Cramer's rule to solve just for x, inthe system: Al x, |=|—14 [Here Ais the
x; -7
given matrix.
CLOMmEnSs Cube Sony“ « Xe =|
atel [A] we bor
and Axa ¢ eo 1.6 te
-4 O (4
[3-2 -4|
my X2= SKS x2
Aeerccmey fo tome
Ba py
3. Find just the 3” column of A, (the matrix of cofactors of A).
i. ube f= 0 = ES
“=f fee
| 32 (0 +4) = on
y
4.Determine A? = Ax A
oS | «eZ \Gs { 9% ) [ab -4-) (-$ 40+) (to -246),
“4 “5 set on 3 73 ‘ Somphe 4 hove Wh. ating val
ly
'VERSIT Dy,
LiBwary
OF fKIRuT *
WV,(10%) Find the 33 matrix B for which b, “fn . i inj
Mey 35 fits
4 tex
r faa yd)
“ey Ren de 4 120 o 4 ¢
ang x ai iy = AUial=ey Ss - | of Y
443 =e 220) (Z)26
© AQ )20 2(2@)*(1): z \% 36 -2 a
Aes * v\-8h4 te G-4plen]
aren Blea) a4 Ags 2(9)(2)226 ane Ayge y-2U(B)alz -Z
V.(20%) The table below has been provided by the quality control department of a factory:
y
Product 1 (P1) | Product 2 (Pz) | Product 3 (Ps) | tetal
(A)Acceptable 50 42 78 19qo
(B)Unacceptable | 12 8 10 20
Tetof 62 So EB Zoo
One item is randomly taken from the batch. Find the following probabilities:
1. P(A)
F - We : 2 do 3 5 a
. (A ) Se “Ww LL 3 Lo
2. P(AAP,) ;
- Oo + $5 x wl zs jor ; .
_ BE 20 y —- Lo
3. P(BU P2)
- Be $° . 3 = a2 = os¢ |
Soo + Feo 7 Wo 6 a
4. P(Ps| A) we
= PCPA N A) = Fs/we . 48 2 low
F(A | Fo / 206 iy