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Linear Algebra                                                Sachin Kaushal, Lovely Professional University




                    Notes            Unit 9: Representation of Transformations by Matrices


                                     CONTENTS

                                     Objectives
                                     Introduction

                                     9.1  Representation of Transformations by Matrices
                                     9.2  Illustrative Examples
                                     9.3  Summary

                                     9.4  Keywords
                                     9.5  Review Questions

                                     9.6  Further Readings
                                   Objectives


                                   After studying this unit, you will be able to:

                                      Know that the matrix of the linear transformation depends on the basis vectors of  V as
                                       well as basis vectors of W where T is a linear transformation from V to W.

                                      See that the matrix of T depends upon the ordered basis relative to  and  ' and the matrix
                                       of T relative to ordered basis   is different from the previous matrix.
                                      See that when T defines a transformation from  V to V then the idea of similar matrices
                                       does come up.
                                      Understand how to find the matrix of T with the help of detailed solved examples.

                                   Introduction


                                   With the help of linear transformation one can deduce the rules for addition of matrices and
                                   multiplication of two matrices.

                                   One can also understand geometrically the meaning of linear transformation clearly.

                                   9.1 Representation of Transformations by Matrices

                                   Although we have been discussing linear transformations for some time, it has always been in
                                   a detached way; to us a linear transformation has been a symbol (very often  T) which acts in a
                                   certain way on a vector  space. When  one gets right down  to it, outside of the few concrete
                                   examples encountered in the problems, we have really never come face to face with specific
                                   linear transformations. At the same time it is clear that if one were to pursue the subject further
                                   there would often arise the need of making a thorough and detailed study of a given linear
                                   transformation. To mention one precise problem, presented with a linear transformation; how
                                   does go about, in a “practical” and computable way, finding its characteristic roots?
                                   What we seek first is a simple notation, or, perhaps more accurately, representation, for linear
                                   transformations. We shall accomplish this by use of a particular basis of the vector space and by




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