International Information Technology University Department of Information Systems and Mathematical Modeling Mathematic in Economic Lesson 1 Matrix. Determinants. Ph. D Alipova B. N. Mathematic in Economic / Ph. D Alipova B. N. 1
Linear Equations The convention mentioned above is simply the rule concerning the multiplication of matrices. These arrays of real numbers of the form Mathematic in Economic / Ph. D Alipova B. N. 2
Matrix Definition Mathematic in Economic / Ph. D Alipova B. N. 3
Elementary Row Operations A system of m linear equations of the form (1) The system can be represented by array (2) Mathematic in Economic / Ph. D Alipova B. N. 4
Addition and subtraction F F The matrix F obtained from A by multiplying each entry of A by -1 Mathematic in Economic / Ph. D Alipova B. N. 5
Arithmetic rules with Matrices Mathematic in Economic / Ph. D Alipova B. N. 6
Multiplication by a real number (Multiplication by scalar) Suppose that Mathematic in Economic / Ph. D Alipova B. N. 7
Multiplication of Matrices Suppose that Mathematic in Economic / Ph. D Alipova B. N. 8
Transpose of a matrix Properties of transpose 1. (A’)’=A 2. (λA)’=λA’ 3. (A+B)’=A’+B’ 4. (AB)’=B’A’ Mathematic in Economic / Ph. D Alipova B. N. 9
Row Echelon Form Reduced Row Echelon Form 0 0 0 0 Mathematic in Economic / Ph. D Alipova B. N. 10
Illustration Mathematic in Economic / Ph. D Alipova B. N. 11
Determinant Matrix 2 x 2 Matrix 3 x 3 Rule of triangles or Rule of Sarrus Matrix nxn Mathematic in Economic / Ph. D Alipova B. N. 13
Example Mathematic in Economic / Ph. D Alipova B. N. 14
Application to Linear Equation We now return to the problem mentioned above. Consider the two equations (consistent system) Mathematic in Economic / Ph. D Alipova B. N. 15
Example Mathematic in Economic / Ph. D Alipova B. N. 16
Row operations on determinants Column operations on determinants Mathematic in Economic / Ph. D Alipova B. N. 17
Next Lesson is Inverse Matrix Mathematic in Economic / Ph. D Alipova B. N. 18