Business Mathematics PDF Notes
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This document is a set of notes on business mathematics, focusing on matrices and determinants. It covers topics such as matrix definitions, types of matrices, algebra of matrices, determinants, and solving systems of linear equations. It's appropriate for an undergraduate-level course.
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Business Mathematics 1 Block – 1: Matrices and Determinants Notes...
Business Mathematics 1 Block – 1: Matrices and Determinants Notes e Course Contents: in Definition of a Matrix Types of Matrices Algebra of Matrices nl Properties of Determinants Adjoint of a Matrix O Inverse of Matrix The Rank of a Matrix Solution of Linear Equation System by Cramer’s rule ity Solution of Linear Equation System by Matrix Inverse Method Key Learning Objectives: At the end of this block, you will be able to: rs 1. Define matrix 2. Identify types of matrices 3. Describe algebra of matrices ve 4. Describe properties of determinant 5. Define adjoint and inverse of a matrix 6. Evaluate the solution system of linear equations by Cramer’s rule ni 7. Evaluate the solution system of linear equations by Matrix Inverse Method Structure: U Unit 1.1: Definition of Matrix 1.1.1 Introduction ity 1.1.2 Definition of Matrix 1.1.3 Types of Matrices 1.1.3.1 Row and Column Matrices m 1.1.3.2 Zero or Null Matrix 1.1.3.3 Square Matrix 1.1.3.4 Diagonal Matrix )A 1.1.3.5 Rectangular Matrix 1.1.3.6 Scaler Matrix 1.1.3.7 Symmetric Matrix (c 1.1.3.8 Skew-symmetric Matrix 1.1.3.9 Unit or Identity Matrix Amity Directorate of Distance & Online Education 2 Business Mathematics 1.1.3.10 Upper Triangular Matrix Notes e 1.1.3.11 Lower Triangular Matrix 1.1.4 Equal Matrix in Unit 1.2: Algebra of Matrices 1.2.1 Introduction nl 1.2.2 Algebra of Matrices 1.2.2.1 Addition of Matrices O 1.2.2.2 Difference of two Matrices 1.2.2.3 Multiplication of Matrices 1.2.2.4 Negative Matrix ity 1.2.3 Properties of Matrix Addition 1.2.4 Properties of Multiplication of Matrices 1.2.5 Transpose of a Matrix rs 1.2.6 Properties of Transpose of Matrices Unit 1.3: Determinants ve 1.3.1 Introduction 1.3.2 Determinants 1.3.3 Properties of Determinants ni Unit 1.4: Rank and Inverse of a Matrix 1.4.1 Introduction U 1.4.2 Minor and Cofactors 1.4.3 Adjoint of Matrix 1.4.4 Singular Matrix ity 1.4.5 Non-singular Matrix 1.4.6 Inverse Matrix 1.4.7 Rank of a Matrix m Unit 1.5: Linear Equation 1.5.1 Introduction )A 1.5.2 Linear equation 1.5.2.1 Solution of a system of Linear equations by Cramer’s rule 1.5.2.2 Solution of a system of Linear equations by Matrix Inverse Method (c Amity Directorate of Distance & Online Education Business Mathematics 3 Unit - 1.1: Definition of Matrix Notes e Unit Outcome: in At the end of this unit, you will be able to: Define Matrix nl Define various types of Matrices Define Equal Matrix O 1.1.1 Introduction Knowledge of matrices is required in various branches of mathematics. Matrix is one of the most powerful tools of mathematics. Compared to other straightforward ity methods, this mathematical tool makes our work much easier. The concept of the matrix evolved as an attempt to solve the system of linear equations in a short and simple form. Matrix notation or representation and operations are used to create electronic spreadsheet programs for the personal computer that is used in various fields of commerce and science like budgeting, sales projection, cost estimation, analysis of the rs result of an experiment, etc. In this unit, we will discuss the matrix, equal matrix and its various types. ve 1.1.2 Definition of Matrix An arrangement of m x n numbers or functions in the form of m horizontal lines (called rows) and n vertical lines (called columns), is called a matrix of the type m by n (or m x n). ni Such an array is enclosed by the bracket [ ]. Each of the m, n numbers constituting the matrix is called an element of the matrix. U The location of each element in the matrix is fixed. Therefore, the elements of the matrix are represented by letters which have two subscripts. The first subscript row and the second subscript column reveal which row and which column the element is in. Thus, the element in the ith row and jth column is written with aij. Therefore, the matrix in ity the m row and n column is often written as follows a11 a1n Amn m a amn m1 This is called a matrix of m x n. )A 2the8number The first letter of the m x n represents 3 of rows in the matrix A and the second letter the number of its columns. 5 7 4 Hence, we can say: 2 5 2 8 3 8 7 (c 5 7 4 is a 2 x 3 matrix, and a 3 x 2 matrix. 3 4 2 5 Amity Directorate of Distance & Online Education 8 7 2 4 3 4 5 8 32 2 8 38 7 5 75 47 4 2 8 3 2 8 3 3 4 2 5 5 7 4 25 8 2 8 7 43 2 5 2 5 7 43 8 7 8 7 4 2 5 4 Business Mathematics 1.1.3 Types of Matrices 225 875 43 3 4 8 7 Notes 2 5 3 4 5 e 8 7 1.1.3.1 Row and 225Column75 4matrix- 8 3 2 A matrix having only 3 4 row is called a row one matrix while the one having 8 7 one 0 as0a column 0 83 47only column is known 4 2 matrix. in 5 7 4 23 45 4 0 0 2 0 Example 1.1.1 [2 2836 3]47 is a (1 x3)row 5 matrix while 4 is a (3 x 1) column matrix. 422 5 5 0 0 5 0 nl 23 4 0 0 0 0 0 0 8 4 5 7 0 each 0 of 0 whose 1.1.3.2 Null Matrix- 4 Anm x n0matrix 0 0 elements is 0, is called a null matrix of the type m x 3 5 4 0 0 0 0 0 0 25 n. 0 0 0 40 0 0 O 20 0 0 0 0 0 0 0 0 0 0 0 Example 1.1.2 0 5 0 0 , 0 0 0 00 and are null matrices of the type 40 0 0 0 0 0 0 00 0 0 0 0 0 0 0 0 0 0 0 05 0 0 ity 0 0 0 2 x 3, 3 x 3 and 2 x 2, 0respectively. 0 0 A aij0 nn0 0 0 0 0 0 00 0 0 1.1.3.3 Square Matrix- 0 0 An 0 mx n matrix 0 0for which m = n, i.e., the number of rows 0 0 0 0 0 1matrix 90 of25 equals the number of0 columns 0 0 is called0 a 0square 0order n or an n- rowed 0 0 0 square matrix. 0 0 0 4 12 30 0 0 The element aij of elements of the matrix 0 0 0 A aij nn 00a square A0and 0 0aij 0nn 4 12 0 rs 0 0 0 1 9 25 the line along 1 30 which 8 16 32 00 0 matrix, A aij nn for which i = j, is called the diagonal they 9 25 1 lie is 0 A aij nn called 0 or simply the diagonal ve 4 12 30 0 21 0 9 25 of the matrix. A0 0aij nn A10 0a9ij n25 8 16 32 n 8 16 32 0 04 3 12 30 Example 1.1.3 4 1 12 9 25 is a square matrix of order A1 0 0a9ij 30 1 0 0 8 16 3. 32 n25 n 1 0 0 1 2 3 ni 8 4 16 12 30 32 A4 12 30 0 2 0 2 314 0 0 which 1.1.3.4 Diagonal 8 1 16 Matrix- a9ij n2532 A 0 2 0 each one of the non-diagonal n square matrix in 18 16 0 0 32 0 0 3 0 2 0 matrices is 0, is called4a diagonal 10 12 30 matrix. 0 0 3 U 209 025 2 0 0 0 0 3 18 16 0 032 1 2 3 0 2 0 40 12 20 0330 1 2 3 of order 3 x 3. Example 1.1.4 0 2 0 is 3 4 matrix 2a diagonal 180 16 0 0332 2 3 4 0 01 2 2 3 10 20 33 2 3 4 ity 0 2 0 2 0 0 1 1.3.1.5 Rectangular 2 230Matrix- 430 A m2x n 0matrix 1 in 3 which 4 the number of rows and 0 20 33 0 2 0 0 columns is not same,1 20 32 40 is called a rectangular 0 2 0 3 22 5 0 0 matrix. 2 40 0 0 2 0 30 4 5 0 6 2 0 1 20 33 0 0 2 Example 1.1.5 2 0 20 0 is a rectangular m matrix of order 2 x 3. 22 30 40 1 3 4 0 0 2 10 20 320 1 3 4 1.1.3.6 Scalar Matrix- 0 2 A0diagonal 3 2 matrix 5 in which all the diagonal elements are 2 3 40 0 0 2 3 2 5 1 3 4 0 03 42 4 5 6 )A equal is called a scaler 1 matrix. 3 2 5 0 213 203 405 2 0 4 5 6 4 5 6 1 0 03 42 3 2 5 Example 1.1.6 0 4 5 60 is a scaler matrix of order 3 x 3. 1 3 2 5 4 035 4 0 62 43 25 65 (c 1 3 4 4 5 6 3 2 5 Amity Directorate of Distance & Online Education 4 5 6 0 0 3 1 2 3 2 3 4 A' A ' Business A A Mathematics 2 0 0 5 ' 0 2 0 A A ' A aij to be symmetric if ' A A A' 1.1.3.7A A A i.e., if A aij Symmetric ' Matrix- A square matrix is said n Notes e A' A A A n 0 0 2 A a A aij A aij then A is called symmetric matrix ij n iff a ij a ji i & j. A aij n ' a i& j n aij A jiA A A1A' ' a aij3Aij 4n n in A An a a Ai' & A jA' A a a i & j a ij' a ji i & j ij ji ij a ji a i &j A A Example Aaij 1.1.7 a 3ij ' 2aAajiij 5 A & iis& ajsymmetric matrix of order 3 x 3. ij ji a a i j 4 5 ij 6nA A A aAij naij n n ij A ji a n ' ' A A A' A A ' A nl A a aija i & j ' AaA ' a Aji ij jin A ij' Aa ij n i& j A aij A 1.1.3.8 aij Skew–Symmetric a A a jiAMatrix Ai &ja–ij Ana square i& a ji0matrix x j y is said to be skew–symmetric n ij ij A anij if 0A ' x A yi.e., if A A aA ' ijaaijjiAthen iA &isj called skew–symmetric x 0 z matrix. n 'A ij a n O A A ij n0 n x Ay A ' 0 x y 0x x0 yz 0 x y A aij xaA yx 0 z y z 0 x 0z z x 0 ' 0 A 0 x y y z n0 a x 0 z A ij ij aijajin i& j n A aij xA x 0a0 zzy isaz skew–symmetric 0 1 n 0 matrix. y z 0 y Example. z 0 1.1.8 y z 0 1 00 x y y0A0y'z xxzA n 0y ij ity 0 y 0 x y x01 0 z x 0 1 z 0 0 1 1 0 10 1.1.3.9 Unit or identity 0 x 0matrix- x z y Scalar xmatrix 0 z each of whose diagonal0 11element 0 is 0 y1 z 0 11A y 0 aijz 00 1 0 1 unity, is called a unit matrix 0 0z an yx or n0identity z matrix. y 1Itzis0represented 0 0 by ‘I’. 1 0 0 0 01 1 0 1 0 1 0 y 1 0 0 x1 y 0 0 z 0 1 0 0 rs 10 01 0 1 0 1 00 0 1 0 11 00 0 00Example 1 0 1 1 0 1 010 100 1.1.9 x 0 1 , 0 0 z 1 0 0 1 is an Identity matrix of order and 0 21x 20and 1 0 0 01 y100z0 00 1 0 0 1 0 1 0 0 1 0 6 01 1 0 0 4 2 6 0 0 1 ve 3 4x 3,2respectively. 0 0 10 01 0 0 1 1 0 0 0 5 3 0 5 1 3 0 0101 1010 0004 2 60 1 0 4 2 6 40 1.1.3.10 2 6 4 2 below 6 0 0 50 0 361 Upper Triangular matrix- A square 4020 2061610 5 3 0 matrix0 6 in which each 0element 5 3 4 principal the diagonal 0is0 0,01is called 10 an upper 0 triangular 0 1 matrix. 0 5 3 0 05 53 30 0 6 0 0 6 0 4 0 2 6 6 041 020 160 4 0 0 0 0 6 ni 4 0 0 0 0 4 0 20 6 6 6 4 2 6 0Example 5 3 1.1.10 0 0 51 304is 0called 0an upper 2 5triangular 0 matrix oforder 4 0 3 x03. 42 05 0 04 52 36 4 0 4000 0000 0612 5 0 0 5 3 3 4 6 2 5 0 0 23 0 54 0 066 4 00 05 63 2 5 0 U 0 0 6 4 6 above 2 triangular 25 50 03matrix- 4 6A square which each 3element 3 41.1.3.11 4 0 6 0 Lower 0 4 4 2 06 0 6 a matrix c e in 3 4 6 the a principal c e diagonal 3 is 4 0,0 4 is called 0 6 a lower4triangular 0 0 matrix. 2 5 0 3 240 565 03a c e b d f ab cd ef 24 50 00 2 5 0 a c e b ad cf e ity b 3 d 4 f 6 a3 0 c40 e66b d f Example a c 1.1.11 32 45 60 is a lower e 4a 6 b matrix of order 3 x 3.b d f 3 triangular a b b bd d f f c d ca d c e 3a 4 4c0 6e0a b a b a b a c e a c e e f c aas b ceb1.1.4 d Equal f Matrices-a abb2 bd5Two f0cmatrices d A and B are said to be, written d A = B, if df ba dand c fe corresponding b d elements are of the same f are equal. e cf d m they c type c d3d 4 their 6e f e a f b ba db f a c e e f a c e e ae f bf a bb d f ab c cd d ef c a d c e a c e a c e Example 1.1.12ca db and c d are not equal but a c eand )A aeb cfd e bf d f b e d f f b d f a ec fd c e e fa c e b d f a c e b bd d f f aba cd c ef eare equal eamatrix. a cf b ea c e b d f a c e a c e a c e b ad cf e bb d d f f a abcc cdedefb d f ba dc fe b d f b d f (c b bde d fff a c e ba dc ef b d f a a c c e e a c e bab ddc fef b d f b d f Amity Directorate of Distance & Online Education b d f a c e b d f 6 Business Mathematics Summary: Notes e An arrangement of m x n numbers or functions in the form of m horizontal lines (called rows) and n vertical lines (called columns), is called a matrix of in the type m by n (or m x n). A matrix having only one row is called a row matrix while the one having only one column is known as a column matrix. nl A m x n matrix each of whose elements is 0, is called a null matrix of the type m x n. A m x n matrix for which m = n, i.e., the number of rows equals the number of O columns is called a square matrix of order n or an n- rowed square matrix. A square matrix in which each one of the non-diagonal matrices is 0, is called a diagonal Matrix. ity A m x n matrix in which the number of rows and columns is uneven is called a rectangular matrix. A diagonal matrix in which all the diagonal elements are equal is called a scaler matrix. rs A square matrix is called a symmetric matrix if for every value of i and j aij = aji. Scalar matrix, each of whose diagonal element is unity, is called a unit matrix or an identity matrix. It is represented by ‘I’. ve A square matrix in which each element below the principal diagonal is 0, is called an upper triangular matrix. A square matrix in which each element above the principal diagonal is 0, is called a lower triangular matrix. ni Two matrices A and B are said to be, written as A = B, if they are of the same type and their corresponding elements are equal. U ity m )A (c Amity Directorate of Distance & Online Education Business Mathematics 7 Unit-1.2: Algebra of Matrices Notes e Recall Session: in In the previous unit, you studied about: (a) Define matrix nl (b) Describe various types of matrices (c) Define equal matrices O Unit Outcome: At the end of this unit, you will be able to: Describe algebra of matrices ity Describe properties of matrix algebra Define transpose of a matrix Describe the properties of the transpose of a matrix 1.2.1 Introduction rs In the previous unit, we studied the various types of matrices and equal matrices ve as well. In this unit, we will learn about matrix algebra, properties of matrix algebra, the transpose of a matrix, and the properties of the transpose of a matrix. 1.2.2 Algebra of Matrices ni 1.2.2.1 Addition of Matrices If two matrices A and B are equal in number of rows and the number of columns U is also equal, then A + B is the matrix whose each element is equal to the sum of the corresponding elements of matrices A and B. Thus if a a c c A 1 a21 , aB2 1 c21 c2 ity bA1 bb2 b , dB1 dd2 d 1 2 1 2 AABa1 a1a2 ca1 ac2c1ca2 c2 c then, A bB d, B 1 b d 1 2 2 b1 1b2 b1 1 d21 d1 b22d2d2 m 1.2.2.2 a c a c2 Difference A B 1 of1 Two2 Matrices b d If twoamatrices b d a1 A1 and2cB are 2c equal in number of rows and the number of columns is )A A 1 a21 , aB2 1 c21 c2 also equal, bA1then dB matrix b2A– B is ,the b1 b2 1of Ad2and d whose each element is equal to the difference of the dB.2 Thus if corresponding components 1 AABa1 a1a2 ca1 ac2c1ca2 c2 c Ab bB1b d, B b d 1 1 2 2 1 2 b1 1 d21d1 b2 2d2d2 (c a1 c1 a2 c2 AB a ba d b c d c A 1 1a21 , B1a22 1 2 c21 c2 Amity Directorate of Distance & Online Education bA1 bb2 b ,dB1 dd2 d 1 2 1 2 AB aa11c1a2aac2d1 aadc11c2 aca2 c2d2a d A ABb c b ,dB b c bd 1 1 2 1 1 2 2 2 b11 1 b2 2 1 d11 2 d2 2 2 2 1 2 b1 dA1 b2 d2 , B 1 a a c ac aca112 b b c a c 2 c2 d1 d2 A B a1 c1 a2 c2 a 1 c 11 a c 2 2 b d b d AAABBBA B1 1 1 2 2 bbb11ddbd11bdbb212dadbd22cd2 a c 1 2 2 1 1 2 2 1 A1 B 2 21 1 2 2 a a c c A 1 2 , B 1 b1 2d1 b2 d2 8 b1 b2 d1 d2 Business Mathematics a a2 c1 c2 aaa11 aaa122 a2 ccc11 ccc122 c2 A 1 , B d d Notes AAAA bba1bbc,1,Bb, BBa2, Bddc2 dd d 1 2 1 2 b1 b2 1 2 e then, A B b 1 11 b2 122 2 a1d1 11a2d2 122 2 c1 c2 b1 dA1 b2 d2 , B a c a b a c 1 c b2 c d1 d2 a a1 c1 a2 c2 a c a c222 2 A B in a 1 c 111 a 12 c b d b d AAA BBB A B1 of 1 2 1.2.2.3 Multiplication Two Matrices dbd22cd2 a c 1 2 2 bbb11 dbd11 bdbb212 a 1 1 2 2 d d 21 1 2 2 If A and B are a1 a2 two 1 suchA 1 B 2 c1 c2 matrices that the number of columns of A is equal to the A number of rowsof B, then , B the multiplication b d 1 d 1 of2 A and d b d 2 B matrix will be AB. nl b1 b2 1 2 aaa11 aaa122 a2 ccc11 ccc122 c2 a1 a2 c1 c2 A , B d d Thus ifAAA A bab 1 1c1 b a,2B,d,B1B,aB1c2 a2d2 2 1 2 b1 b2 b b AB b1 11 b2 122 2 ad11 11ad2 2122 2 c1 c2 d d d d d 1 2 O b1c1 bA2d1 b1c2 b2,dB2 a a cc a aca d d ab21daa1ccb2 2 a1aca2dd2 a2dd12 d2 AB a1c1 a2d1 a1c2 a2d2 AB a1c11 1 a2d21 1 a1c12 2 a2d22 2 1 1 1 2 1 1 b c b d b c b d then, AB AAB a AB bijbbc11cc1 b bc d b db c b bc db d 1 1 2 1 1 2 2 2 bd212d11 b 2ab c1c1c22ba 1b d2d2d222a 2c a d 1 1 1 b1AB 2 1 11 21 22 21 1 2 2 2 ity A aa . b1c1 b2d1 b1c2 b2d2 A aij AAAaA 1.2.2.4 Negative aijijaij ij ij Matrix A negative matrix a1 Aa A a adenoted 2 .a . ij of a2 by – A where A aij . AAAA b aaijaijij. .ijA 1 1 b2 A ab1 . b2 a1 a2 a1 a2 rs aaa11 aaa122 a2 aijaa11 aa1aa22a2 A A b b Thus if AA A aA bbc bbe,bthen 1 2 AAA A 1 b b bbb 2 b b1 b2 1 2 A b1 11 b2 122 2 a1ba1211 b12 22 2a1 a2 b d fA A b b a c e a c a e c eb b 1 2 ve 1.2.3 Properties a a cof c Matrix e e 1 Addition 2 A A A A A abb bddb fdf f Suppose A,bB, a c e b d f d f C three matrices are of same order. A ' c d . A (i) Commutative a b aLaw: b A b+ B d= B f+A a b aea bf b c' Law: dc. A +.(B + C) = (A + B) + C A ' c d . ni AA ' (ii) Associative ' A A ' ' c d. a b c d. d A' Identity: A e f (iii) Additive eee ffefAA'f+ Oc = Ad =.O + A kA e of forder m + n. ' ' where O ' is kA a' ' null matrix A ' A U ' AA'A'' AA'AA A ' (iv) Additive Inverse: A +' (– C) = O ' ' 'A ' B A'' A ' ' A B kA kA ' – AkA kA iskA kA called ' kA kA 'the kA '' kA ' additive inverse of A. ' kA IfA+kA ' ity AB A B A' B' ' ' (v) Cancellation B ' ''A Law: ' B= ' A+C A A A B A' B' B A B ' B A A '' BAB ' ' B ' than B = C A B A ' B ' ' AB B ' A' ' '' ' AB Bof' AScalar AB (vi) PropertiesAB ' AB B B ' 'A A ' ' B' ' A 'Multiplication: k(A + B) = kA + kB and (k1 + k2) A = k1 A + k2 A, where k, k1 and AB2arek Bconstant or scaler quantity. ' ' A' m 1.2.4 Properties of Multiplication of Matrices Suppose A, B, C are three matrices. )A (i) Associative Law: (AB).C = A.(BC) (ii) Distributive Law: (a) A(B + C) = AB + BC (c (b) (A + B) C = AC + BC (iii) Identity Law: | A = A | = A Amity Directorate of Distance & Online Education A aij a1c1 a2d1 a1c2 a2d 2 AB b2d2 a . b1c1 b2d1 b1c2A ij A aij a a a1 a2 Business Mathematics A 1 2 A 9 b b2 A of aija.Matrix b1 b2 1 1.2.5 Transpose Notes e The of a matrix is a matrix formed,a c e a1 a2 Aa1 from a2 the original where the rows of the original A column matrix are the of the A transpose b d The b matrix. f transpose of matrix A is denoted by in A′. b1 b2 1 b2 a b a c e Thus if A then A ' c d . nl b d f e f a b A'of Matrices ' A A ' c ofdTranspose 1.2.6 Properties . O (a) (A′) = A e f kA kA' ' (b) (kA) = kA′ A' ' A A B ' A ' B ' ity (c) (A + B) = A′ + B′ kA=B′A′ ' (d) (AB)′ kA ' AB ' B' A' Summary: A B A ' B ' ' If two matrices AB B ' AA ' rs ' and B are equal in the number of rows and the number of columns is also equal, then A + B is the matrix whose each element is equal to the sum of the corresponding elements of matrices A and B. ve If two matrices A and B are equal in the number of rows and the number of columns is also equal, then A – B is the matrix whose each element is equal to the difference of the corresponding components of A and B. If A and B are two such matrices that the number of columns of A is equal to ni the number of rows of B, then the multiplication of A and B matrix will be AB. The negative form of the matrix A = – A. U The of a matrix is a matrix formed, from the original where the rows of the original matrix are the column of the transpose matrix. The transpose of matrix A is denoted by A′. ity m )A (c Amity Directorate of Distance & Online Education 10 Business Mathematics Unit - 1.3: Determinants Notes e Recall Session: in In the previous unit, you studied about: (a) Describe algebra of matrices nl (b) Describe properties of matrix algebra (c) Define transpose of a matrix (d) Describe the properties of the transpose of a matrix O Unit Outcome: At the end of this unit, you will be able to: ity Define determinants Describe prope