<< Chapter < Page Chapter >> Page >
This chapter covers principles of matrices. After completing this chapter students should be able to: complete matrix operations; solve linear systems using Gauss-Jordan method; Solve linear systems using the matrix inverse method and complete application problems.

Introduction to matrices

A vendor sells hot dogs and corn dogs at three different locations. His total sales (in hundreds) for January and February from the three locations are given in the table below.

January February
Hot Dogs Corn Dogs Hot Dogs Corn Dogs
Place I 10 8 8 7
Place II 8 6 6 7
Place III 6 4 6 5

Represent these tables as 3 × 2 size 12{3 times 2} {} matrices J size 12{J} {} and F size 12{F} {} , and answer [link] , [link] , [link] , and [link] . problems 1 - 4.

Determine total sales for the two months, that is, find J + F size 12{J+F} {} .

18 15 14 13 12 9 size 12{ left [ matrix { "18" {} # "15" {} ##"14" {} # "13" {} ## "12" {} # 9{}} right ]} {}
Got questions? Get instant answers now!

Find the difference in sales, J F size 12{J - F} {} .

Got questions? Get instant answers now!

If hot dogs sell for $3 and corn dogs for $2, find the revenue from the sale of hot dogs and corn dogs. Hint: Let P size 12{P} {} be a 2 × 1 size 12{2 times 1} {} matrix. Find J + F P size 12{ left (J+F right )P} {} .

84 68 54 size 12{ left [ matrix { "84" {} ##"68" {} ## "54"} right ]} {}
Got questions? Get instant answers now!

If March sales will be up from February by 10%, 15%, and 20% at Place I, Place II, and Place III, respectively, find the expected number of hot dogs, and corn dogs to be sold in March. Hint: Let R size 12{R} {} be a 1 × 3 size 12{1 times 3} {} matrix with entries 1.10, 1.15, and 1.20. Find RF size 12{ ital "RF"} {} .

Got questions? Get instant answers now!

Determine the sums and products in the next 5 problems. Given the matrices A size 12{A} {} , B size 12{B} {} , C size 12{C} {} , and D size 12{D} {} as follows:

A = 3 6 1 0 1 3 2 4 1 size 12{A= left [ matrix { 3 {} # 6 {} # 1 {} ##0 {} # 1 {} # 3 {} ## 2 {} # 4 {} # 1{}} right ]} {} B = 1 1 2 1 4 2 3 1 1 size 12{B= left [ matrix { 1 {} # - 1 {} # 2 {} ##1 {} # 4 {} # 2 {} ## 3 {} # 1 {} # 1{}} right ]} {} C = 1 2 3 size 12{C= left [ matrix { 1 {} ##2 {} ## 3} right ]} {} D = 2 3 2 size 12{D= left [ matrix { 2 {} # 3 {} # 2{}} right ]} {}

3A 2B size 12{3A - 2B} {}
7 20 1 2 5 5 0 10 1 size 12{ left [ matrix { 7 {} # "20" {} # - 1 {} ##- 2 {} # - 5 {} # 5 {} ## 0 {} # "10" {} # 1{}} right ]} {}
Got questions? Get instant answers now!
AB + BA size 12{ ital "AB"+ ital "BA"} {}
Got questions? Get instant answers now!
A 2 size 12{A2} {}
11 28 22 6 13 6 8 20 15 size 12{ left [ matrix { "11" {} # "28" {} # "22" {} ##6 {} # "13" {} # 6 {} ## 8 {} # "20" {} # "15"{}} right ]} {}
Got questions? Get instant answers now!
2 BC size 12{2 ital "BC"} {}
Got questions? Get instant answers now!
2 CD + 3 AB size 12{2 ital "CD"+3 ital "AB"} {}
40 72 61 38 33 23 39 63 51 size 12{ left [ matrix { "40" {} # "72" {} # "61" {} ##"38" {} # "33" {} # "23" {} ## "39" {} # "63" {} # "51"{}} right ]} {}
Got questions? Get instant answers now!

Let E = m n p q size 12{E= left [ matrix { m {} # n {} ##p {} # q{} } right ]} {} and F = a b c d size 12{F= left [ matrix { a {} # b {} ##c {} # d{} } right ]} {} , find EF size 12{ ital "EF"} {} .

ma + nc mb + nd pa + qc pb + qd size 12{ left [ matrix { ital "ma"+ ital "nc" {} # ital "mb"+ ital "nd" {} ##ital "pa"+ ital "qc" {} # ital "pb"+ ital "qd"{} } right ]} {}
Got questions? Get instant answers now!

Let G = 3 6 1 0 1 3 2 4 1 size 12{G= left [ matrix { 3 {} # 6 {} # 1 {} ##0 {} # 1 {} # 3 {} ## 2 {} # 4 {} # 1{}} right ]} {} H = x y z size 12{H= left [ matrix { x {} ##y {} ## z} right ]} {} , find GH size 12{ ital "GH"} {} .

Got questions? Get instant answers now!

Express the following systems as AX = B size 12{ ital "AX"=B} {} , where A size 12{A} {} , X size 12{X} {} , and B size 12{B} {} are matrices.

4x 5y = 6 size 12{4x - 5y=6} {}
5x 6y = 7 size 12{5x - 6y=7} {}
4 5 5 6 x y = 6 7 size 12{ left [ matrix { 4 {} # - 5 {} ##5 {} # - 6{} } right ]left [ matrix { x {} ##y } right ]= left [ matrix { 6 {} ##7 } right ]} {}
Got questions? Get instant answers now!
x 2y + 2z = 3 size 12{x - 2y+2z=3} {}
x 3y + 4z = 7 size 12{x - 3y+4z=7} {}
x 2y 3z = 12 size 12{x - 2y - 3z= - "12"} {}
Got questions? Get instant answers now!
2x + 3z = 17 size 12{2x+3z="17"} {}
3x 2y = 10 size 12{3x - 2y="10"} {}
5y + 2z = 11 size 12{5y+2z="11"} {}
2 0 3 3 2 0 0 5 2 x y z = 17 10 11 size 12{ left [ matrix { 2 {} # 0 {} # 3 {} ##3 {} # - 2 {} # 0 {} ## 0 {} # 5 {} # 2{}} right ] left [ matrix {x {} ## y {} ##z } right ]= left [ matrix { "17" {} ##"10" {} ## "11"} right ]} {}
Got questions? Get instant answers now!
x + 2y + 3z + 2w = 14 x 2y z = 5 y 2z + 4w = 9 x + 3z + 3w = 15 size 12{ matrix { x {} # +{} {} # 2y {} # +{} {} # 3z {} # +{} {} # 2w {} # ={} {} # "14" {} ##x {} # - {} {} # 2y {} # - {} {} # z {} # {} # {} # ={} {} # - 5 {} ## y {} # - {} {} # 2z {} # {} # {} # +{} {} # 4w {} # ={} {} # 9 {} ##x {} # +{} {} # 3z {} # {} # {} # +{} {} # 3w {} # ={} {} # "15"{} } } {}
Got questions? Get instant answers now!

Systems of linear equations

Solve the following by the Gauss-Jordan Method. Show all work.

x + 3y = 1 size 12{x+3y=1} {}
2x 5y = 13 size 12{2x - 5y="13"} {}

(4,-1)

Got questions? Get instant answers now!
x y z = 1 size 12{x - y - z= - 1} {}
x 3y + 2z = 7 size 12{x - 3y+2z=7} {}
2x y + z = 3 size 12{2x - y+z=3} {}
Got questions? Get instant answers now!
x + 2y + 3z = 9 size 12{x+2y+3z=9} {}
3x + 4y + z = 5 size 12{3x+4y+z=5} {}
2x y + 2z = 11 size 12{2x - y+2z="11"} {}

(2, -1, 3)

Got questions? Get instant answers now!
x + 2y = 0 size 12{x+2y=0} {}
y + z = 3 size 12{y+z=3} {}
x + 3z = 14 size 12{x+3z="14"} {}
Got questions? Get instant answers now!

Two apples and four bananas cost $2.00 and three apples and five bananas cost $2.70. Find the price of each.

(0.4, 0.3)

Got questions? Get instant answers now!

A bowl of corn flakes, a cup of milk, and an egg provide 16 grams of protein. A cup of milk and two eggs provide 21 grams of protein, and two bowls of corn flakes with two cups of milk provide 16 grams of protein. How much protein is provided by one unit of each of these three foods.

Got questions? Get instant answers now!
x + 2y = 10 size 12{x+2y="10"} {}
y + z = 5 size 12{y+z=5} {}
z + w = 3 size 12{z+w=3} {}
x + w = 5 size 12{x+w=5} {}

(4, 3, 2, 1)

Got questions? Get instant answers now!
x + w = 6 size 12{x+w=6} {}
2x + y + w = 16 size 12{2x+y+w="16"} {}
x 2z = 0 size 12{x - 2z=0} {}
z + w = 5 size 12{z+w=5} {}
Got questions? Get instant answers now!

Systems of linear equations – special cases

Solve the following inconsistent or dependent systems by using the Gauss-Jordan method.

2x + 6y = 8 size 12{2x+6y=8} {}
x + 3y = 4 size 12{x+3y=4} {}
( 4 3t size 12{4 - 3t} {} , t size 12{t} {} )
Got questions? Get instant answers now!

The sum of the digits of a two digit number is 9. The sum of the number and the number obtained by interchanging the digits is 99. Find the number.

Got questions? Get instant answers now!
2x y = 10 size 12{2x - y="10"} {}
4x + 2y = 15 size 12{ - 4x+2y="15"} {}

Inconsistent system, no solution

Got questions? Get instant answers now!
x + y + z = 6 size 12{x+y+z=6} {}
3x + 2y + z = 14 size 12{3x+2y+z="14"} {}
4x + 3y + 2z = 20 size 12{4x+3y+2z="20"} {}
Got questions? Get instant answers now!
x + 2y 4z = 1 size 12{x+2y - 4z=1} {}
2x 3y + 8z = 9 size 12{2x - 3y+8z=9} {}

( 3 4 / 7t size 12{3 - 4/7t} {} , 1 + 16 / 7t size 12{ - 1+"16"/7t} {} , t size 12{t} {} )

Got questions? Get instant answers now!

Jessica has a collection of 15 coins consisting of nickels, dimes and quarters. If the total worth of the coins is $1.80, how many are there of each? Find all three solutions.

Got questions? Get instant answers now!

The latest reports indicate that there are altogether 20,000 American, French, and Russian troops in Bosnia. The sum of the number of Russian troops and twice the American troops equals 10,000. Furthermore, the Americans have 5,000 more troops than the French. Are these reports consistent?

No, they are not consistent.

Got questions? Get instant answers now!

Questions & Answers

the definition for anatomy and physiology
Watta Reply
what is microbiology
Agebe Reply
What is a cell
Odelana Reply
what is cell
Mohammed
how does Neisseria cause meningitis
Nyibol Reply
what is microbiologist
Muhammad Reply
what is errata
Muhammad
is the branch of biology that deals with the study of microorganisms.
Ntefuni Reply
What is microbiology
Mercy Reply
studies of microbes
Louisiaste
when we takee the specimen which lumbar,spin,
Ziyad Reply
How bacteria create energy to survive?
Muhamad Reply
Bacteria doesn't produce energy they are dependent upon their substrate in case of lack of nutrients they are able to make spores which helps them to sustain in harsh environments
_Adnan
But not all bacteria make spores, l mean Eukaryotic cells have Mitochondria which acts as powerhouse for them, since bacteria don't have it, what is the substitution for it?
Muhamad
they make spores
Louisiaste
what is sporadic nd endemic, epidemic
Aminu Reply
the significance of food webs for disease transmission
Abreham
food webs brings about an infection as an individual depends on number of diseased foods or carriers dully.
Mark
explain assimilatory nitrate reduction
Esinniobiwa Reply
Assimilatory nitrate reduction is a process that occurs in some microorganisms, such as bacteria and archaea, in which nitrate (NO3-) is reduced to nitrite (NO2-), and then further reduced to ammonia (NH3).
Elkana
This process is called assimilatory nitrate reduction because the nitrogen that is produced is incorporated in the cells of microorganisms where it can be used in the synthesis of amino acids and other nitrogen products
Elkana
Examples of thermophilic organisms
Shu Reply
Give Examples of thermophilic organisms
Shu
advantages of normal Flora to the host
Micheal Reply
Prevent foreign microbes to the host
Abubakar
they provide healthier benefits to their hosts
ayesha
They are friends to host only when Host immune system is strong and become enemies when the host immune system is weakened . very bad relationship!
Mark
what is cell
faisal Reply
cell is the smallest unit of life
Fauziya
cell is the smallest unit of life
Akanni
ok
Innocent
cell is the structural and functional unit of life
Hasan
is the fundamental units of Life
Musa
what are emergency diseases
Micheal Reply
There are nothing like emergency disease but there are some common medical emergency which can occur simultaneously like Bleeding,heart attack,Breathing difficulties,severe pain heart stock.Hope you will get my point .Have a nice day ❣️
_Adnan
define infection ,prevention and control
Innocent
I think infection prevention and control is the avoidance of all things we do that gives out break of infections and promotion of health practices that promote life
Lubega
Heyy Lubega hussein where are u from?
_Adnan
en français
Adama
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get Jobilize Job Search Mobile App in your pocket Now!

Get it on Google Play Download on the App Store Now




Source:  OpenStax, Applied finite mathematics. OpenStax CNX. Jul 16, 2011 Download for free at http://cnx.org/content/col10613/1.5
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Applied finite mathematics' conversation and receive update notifications?

Ask